The ongoing failure to restore powersharing in Northern Ireland is a shame on all the region's politicians, Arlene Foster has said.
The DUP leader urged rivals to come together to strike a deal to resurrect the devolved executive ahead of another round of talks in Belfast.
The DUP and Sinn Féin go into the negotiations on the back of disappointing election results - with many interpreting the General Election as the public passing judgment on the parties' failure to restore the Assembly.
Secretary of State Julian Smith is holding a round of bilateral meetings with the DUP, Sinn Féin, UUP, SDLP and Alliance Party at Stormont House this morning, with a roundtable session with all the party leaders due later in the week.
SDLP leader Colum Eastwood said the electorate had delivered a message to the politicians that they needed to get back to work.
"People have made it very clear they are sick of this - they are sick of this standoff, it hasn't solved anybody's problems, it hasn't taken anybody off a waiting list, it hasn't fixed nurses' pay, it hasn't done any of that.
"The only way you do that is by getting into government and taking responsibility."
He added: "The idea we can be off the pitch any longer is just not acceptable anymore. I think the public have made it very, very clear. They want Stormont back up and running."
Alliance Party leader Naomi Long said a deal could be done ahead of the middle of January, when legislation that gives civil servants added powers to run the north's public services expires.
"We are there to be constructive, we are there to be positive, we are there to deliver an Assembly that actually works for the people of Northern Ireland," she said.
"We have three working weeks to deliver, so this week can't be about people sitting around and licking their wounds or preening themselves after last week's elections.
"The elections are over, we are now down to the hard graft of getting an Assembly functioning. That means looking at difficult choices and reforms that needs to be undertaken so that when that Assembly is up and running - and I believe it must be - that it is actually fit for purpose and capable of delivery.
"People this week need to be focused, not on the political issues that we have been beating to death for the last three years, we need to be focused on what is going on out on our streets.
"We need to be focused on the fact we have a crisis in the health service, we have an impending crisis in our education system, that our infrastructure is under extraordinary pressure - those are the very issues that we were elected to deliver on and those are the issues that we need an Assembly to start to address."
Tánaiste Simon Coveney will also be at Stormont this afternoon for talks.
It is understood that Mr Smith has been working on proposals to break the impasse which he is outline to the parties today.
A spiralling crisis in the north's health service has heaped further pressure on the politicians to get back to work in a devolved legislature.
Healthcare workers will go on strike on Wednesday to protest at pay restraints and staffing shortages.
Irish language activists and healthcare workers staged separate protests outside Stormont House as the talks were taking place inside.
The demonstrations had a festive theme as Unison health union members sang carols with the words changed to highlight their demands for pay parity with workers in the rest of the UK.
UUP leader Steve Aiken said he had raised concerns about the health service during his meeting with Julian Smith.
"The one thing we must see is a responsible and accountable government brought back and one where the challenges of the past are identified and that is going to mean significant changes across the board and if we can't get reformation in the process we have to ask ourselves what's the point of bringing it back.
"If we can't bring it back by the middle of January we must have proper government in Northern Ireland - if that is direct rule, then it's direct rule."
Mr Aiken said it was unlikely a deal would be struck before Christmas.
"I would say that if there is good will I think we might get a deal by the middle of January, but there needs to be good will and there needs to be substantial reform," he said.
Scores of children from Irish language schools wore Santa hats as they marched to the front of Parliament Buildings calling for legislation.
Ahead of the meetings on Monday, Ms Foster said: "It is a shame on all politicians in Northern Ireland that we have not been able to have the institutions up and running again, but we have to now."
She told BBC Radio Ulster: "I fundamentally believe that if there's a will there is a way, and the issues have been talked about now for three years, so there is nothing new on the table - therefore there is every chance we can come to an agreement but there has to be a willingness across the piece.
"For my part there is certainly a willingness from the Democratic Unionist Party."
Sinn Fein's Stormont leader, Michelle O'Neill, said the institutions have to be restored on a "credible and sustainable basis".
"A credible restored Executive must deliver on issues such as public sector pay, safe staffing levels in the health service, economic policies that deliver prosperity and invest in rural communities, and an appropriate welfare mitigation package," she said on Sunday night.
"We will work towards securing agreement on outstanding issues, including an Irish Language Act, reform of the Petition of Concern (contentious Assembly voting mechanism), the legacy of the past and integrity in government.
"I believe they can be resolved if there is the political will to do so. We need a new kind of politics, a new Assembly and a new Executive.
"We need to deliver good government and properly resourced public services to all. We need an Executive which is transparent, accountable and inclusive."
SDLP leader Colum Eastwood said the electorate had delivered a message to the politicians that they needed to get back to work.
"People have made it very clear they are sick of this - they are sick of this standoff, it hasn't solved anybody's problems, it hasn't taken anybody off a waiting list, it hasn't fixed nurses' pay, it hasn't done any of that.
"The only way you do that is by getting into government and taking responsibility."
He added: "The idea we can be off the pitch any longer is just not acceptable anymore. I think the public have made it very, very clear. They want Stormont back up and running."
Powersharing imploded almost three years ago amid a row about a botched green energy scheme.
That rift soon widened and refocused on long-standing disputes over issues such as the Irish language and same-sex marriage.
With same-sex marriage having been legislated for at Westminster earlier this year, the wrangle over the Irish language remains the key stumbling block.
Sinn Fein has made an Irish Language Act a prerequisite of any deal to restore devolution.
The DUP has expressed a willingness to legislate to protect the language, but only as part of broader culture laws which also include the Ulster Scots tradition.
Ahead of the renewed political talks involving the parties, senior health leaders, representing doctors and nurses in Northern Ireland, issued a statement outlining their serious concerns about the situation in the health and social care system.
The British Medical Association, Royal College of Emergency Medicine NI, Royal College of Surgeons of England, Royal College of General Practitioners (NI), Royal College of Nursing, Royal College of Psychiatrists NI, the Royal College of Radiologists UK and the Northern Irish Board of the Royal College of Anaesthetists - which collectively represent thousands of medical and nursing professionals in Northern Ireland - said they were taking the "unusual" step of issuing a joint statement due to the severity of the situation.
The groups called on politicians to get the devolved institutions up and running again with immediate effect.
