The DUP has warned the British Government not to intervene in devolved issues in Northern Ireland to legislate for Irish language protections.
East Antrim MP Sammy Wilson’s comments come after Sinn Féin called on Northern Ireland Secretary Brandon Lewis to pass the laws at Westminster as a way to resolve a political stand-off within the powersharing executive.
“Following the latest demand from (Sinn Féin president) Mary Lou McDonald, the Government must not interfere in devolved issues at the behest of Sinn Fein,” Mr Wilson said.
“The Government foisted the most liberal abortion laws in the British Isles on Northern Ireland. Such actions only served to undermine devolution. To force through the latest Sinn Féin wish list will cause further damage to the credibility of the Northern Ireland Assembly.
“Repeated interventions in devolved matters undermines the manifesto promises of Northern Ireland parties and rightly raises questions about the confidence that voters can have in those they elect if their promises can be causally overridden by the Secretary of State.
“Rather than running to HMG when they can’t get their way, republicans should respect our mandate. Sinn Féin is playing the politics of ransom and are placing culture above health, education and economic recovery.”
A row between the biggest unionist party and Sinn Féin on language legislation could derail the powersharing institutions after Arlene Foster stood down as first minister yesterday.
DUP leader Edwin Poots has said he will support Irish language legislation, but not necessarily before the next assembly election.
Sinn Féin has suggested it may not support the DUP's Paul Givan as first minister unless legislation is approved by ministers before July 10.
If no first minister is agreed within a week then a snap election is likely. If the executive falls, key decisions around lockdown measures and lengthy hospital waiting lists cannot be taken until after an election.
The letter by Sein Féin, addressed to the Executive and the British and Irish governments, stated that an Irish language act must be introduced in this assembly mandate.
"The New Decade New Approach agreement contained a time-focused commitment that the language legislation would be implemented within 100 days," the letter read.
"Due to the pandemic, we can all appreciate the reasons for the initial deadline being missed.
"The legislation, however, is now ready to go and simply awaiting the political green light to proceed."
Sinn Féin Vice President Michelle O'Neill; SDLP leader Colum Eastwood; Alliance leader Naomi Long; Gerry Carroll of People Before Profit and Green Party leader Clare Bailey have all signed the letter.
"Any attempt to renege on agreed Irish language legislation, or indeed frustrate its progress, must be resisted," the letter read.
"If this legislation is not passed within the current mandate, much of the progress we have made in recent years may be undone.
"We also call on the British and Irish Governments to intensify their efforts in their roles as co-guarantors and indeed co-authors of the New Decade New Approach Agreement to facilitate all-party agreement on a timeline for implementation of this legislation within the current mandate.
"The timely passage of this legislation into law will herald an historic moment for the Irish language community."
Sinn Féin has previously accused Mr Poots of acting in bad faith over language legislation.
A party spokesman said: "We do not believe they will deliver on the Irish Language Act."
"Our position is that the nomination for first minister and deputy first minister has to be accompanied by legislation on the Irish language."
Last week, Conradh na Gaelige was granted leave by the High Court in Belfast to apply for a judicial review into the Executive's failure to implement a strategy for the Irish language.