The secretary of state has told Stormont leaders he has asked officials to explore possible avenues to implement organ donation laws in the north in the absence of the powersharing institutions.

The opt-out donation system was passed by MLAs last year but the secondary legislation required to implement it cannot be approved at Stormont due to the political stalemate.

Last month, the five largest parties wrote to Chris Heaton-Harris urging him to intervene to implement the new organ donation law at Westminster.

It was to be named Dáithí’s Law after six-year-old Dáithí Mac Gabhann, from Belfast, who is on the organ transplant waiting list and whose family have campaigned for the new legislation.

Mr Heaton Harris has now written to the Stormont parties. This came on the same day the secretary of state was meeting with Dáithi and his parents at Hillsborough.

Mr Heaton Harris said he shared the family’s “deep disappointment” and “frustration” that the legislation may not be fully implemented by the spring as planned.

While he said he would ask officials to assess how the law could be implemented by the British government, he also urged Northern Ireland MPs to consider tabling a Private Members’ Bill to proceed the issue by that legislative route.

“The change to Northern Ireland’s organ donation law has been a long time coming and the MacGabhann family’s campaign was instrumental in generating momentum for the change to the law,” he wrote in a letter seen by the PA news agency.

“I am extremely frustrated that the inability of MLAs to elect a new speaker could cause delays to the introduction of life-saving legislation.

“That is why I want fully functioning devolved institutions to resume as soon as possible, so MLAs can get back to work and swiftly implement the law that Dáithi and his family have campaigned so tirelessly for.

“I am asking my officials to explore possible avenues for the UK government to progress this issue, should the Assembly fail to do so.

“I would also like to remind MPs from the Northern Ireland parties of the other Parliamentary routes to progress this legislation that continue to be available to them, namely the opportunities that exist to introduce Private Members’ Bills etc.

“This issue demonstrates just how important it is for the Executive to be restored and for the vital business of the Northern Ireland Assembly to resume. This will continue to be my priority.”