The British government published legislation today to hand it powers to compel Northern Ireland to implement more liberal abortion services, despite opposition from the region's first minister and health minister.

Britain's parliament voted in 2019 to legalise abortion in Northern Ireland, allowing terminations without restriction up to 12 weeks and with no time limit in the case of "severe foetal impairment or fatal foetal abnormality".

But while the regional government is allowing early medical abortion up to 10 weeks, it has not implemented the rules in full, forcing some women to travel to other parts of the United Kingdom to access terminations.

"While there may been some inevitable delay by the Department of Health in Northern Ireland in commissioning abortion services, given the unforeseen pressures of responding to the Covid pandemic, almost a year has passed since the Abortion Regulations came into effect," the British government's Northern Ireland Office said in an explanatory note to the proposed legislation.

"We have reached a point where it remains clear that the Department of Health will not move forward to make positive progress on this matter," the note said.

The legislation hands Northern Ireland minister Brandon Lewis "the power that certain public authorities take action", giving him the power to bypass ministerial objections.

Northern Ireland's First Minister Arlene Foster, and her socially conservative Democratic Unionist Party (DUP), have opposed the implementation of the new abortion rules, saying they would represent one of the most liberal abortion rules in Western Europe and lack popular support.

DUP member of parliament Jeffrey Donaldson last week described plans to implement the legislation as "a fundamental breach of the devolution settlement", which grants the Northern Ireland Executive responsibility for health issues.

The region's socially conservative health minister, Robin Swann, a member of the rival Ulster Unionist Party, has repeatedly voiced his opposition to implementing the new services.

Abortion rights activists say opinion polls show Northern Ireland supportive of more liberal abortion rules and accuse the regional administration of violating womens' rights by blocking the services.

The British government says the legislation is required to uphold the country's obligations to the UN Committee on the Elimination of Discrimination against Women, which in 2018 said Northern Ireland's restrictions of abortion represented discrimination against women.

The new legislation is a "necessary and appropriate means of ensuring" that recommendations from the UN body were fulfilled, the Northern Ireland Office note said.

Ms Foster has criticised the Government's intervention on abortion provision in Northern Ireland.

"The action that's been taken today by the Secretary of State is, from our perspective, very much overreach into a devolved space," she told reporters at Stormont.

"It is up to the devolved administration how they deal with these issues and therefore he is acting beyond what he should be doing. He will, of course, say that he's acting under Westminster legislation, that's why he's taking the action that he is.

"The action that he takes today, by way of written ministerial statement and the laying of regulations, does not change what happens in Northern Ireland overnight.

"There is now a period of time where those regulations sit and it's not until they're affirmed by Parliament that he is given the power to direct the Health Minister here in Northern Ireland.

"So nothing changes overnight but our view is very clearly that the Secretary of State should not be overreaching into the devolved space."

Northern Ireland's Deputy First Minister Michelle O'Neill predicted the abortion issue will "come to a head" at Thursday's meeting of the Stormont Executive.

"I think that one year after the legislation has been passed, I think it's so unfair that women have been denied access to modern and compassionate healthcare services," she said.

"The Department of Health have still not commissioned the services that women are entitled to.

"It should be this Executive that decides and makes sure that we deliver these services.

"So I very much urge the Health Minister (Robin Swann) to commission the services. I hope this matter will come to a head in the Executive on Thursday, I think that's where we should be making the decisions around what is modern and compassionate healthcare for all women who are entitled to have that service whenever they find themselves in the most challenging of circumstances."