A Labour MP has said politicians in Northern Ireland must not stop women here from accessing terminations.
Stella Creasy said the reform of abortion legislation, which came into force last night, is the "first step" in ensuring women in Northern Ireland have equal rights to women in England and Wales.
She was speaking as MLAs from a number of political parties returned to the chamber at Stormont yesterday for the first time in more than 1,000 days.
Ms Creasy led a successful push in the Commons earlier this year to extend abortion rights to Northern Ireland.
MPs amended the Northern Ireland (Executive Formation) Bill, to say Westminster would be required to extend the right to abortion if Stormont is not up and running by October 21.
From today, women in Northern Ireland have the right to a termination where there is a risk to their mental or physical health, in cases of serious and fatal foetal abnormalities, or if they have been the victim of a sexual crime including rape or incest.
A moratorium on the prosecution of anyone who undergoes or assists in a termination has been put in place.
The Northern Ireland Office now has until the end of March next year to carry out a public consultation to decide how the service will be provided.
Until then, it is expected that most women seeking a termination will continue to travel to England for the procedure, with costs being covered by the government.
Pro-life organisations have expressed horror at the development and yesterday, some MLAs, led by the DUP, returned to Stormont in an unsuccessful last-ditch attempt to stop the decriminalisation of abortion.
They have vowed to continue fighting for the rights of unborn children after they failed to block the changes yesterday.
However, Ms Creasy last night said: "Today marks the first step in getting women in Northern Ireland equal rights with their counterparts in England and Wales. When it comes to being able to make decisions over their own bodies, women and girls in Northern Ireland will no longer be threatened with the criminal law.
"The legislation that comes into force tomorrow requires the Secretary of State for Northern Ireland to uphold human rights standards for abortion from start to finish.
"It is vital that we do not now see any back-room deals in Parliament on in the Assembly to water down the commitment we made to treat women in Northern Ireland as equals.
"We will accept no more delays in the regulations governing access. Women in Northern Ireland have waited long enough."