A cross-party delegation has handed over thousands of postcards to the Prime Minister demanding protection for Northern Ireland's abortion laws.
Radical new laws are on the cusp of being implemented in the province despite widespread opposition.
The decriminalisation of abortion in Northern Ireland is set to come into effect on October 22 unless Stormont, which has been suspended for over two years, is reinstituted.
Discussing the changes in Westminster on Monday, the Government said there would be a moratorium on prosecutions come October 22, lasting until March 2020.
Pro-life campaigners have been calling for the province's laws to stay as they are. At present, abortions in Northern Ireland are only permitted in very limited circumstances, when there is a serious risk to the mother's mental or physical wellbeing.
The Northern Ireland (Executive Formation) Act 2019 passed by Westminster MPs earlier this year repeals Sections 58 and 59 of the Offences Against The Person Act, making abortion possible up to 28 weeks, far later than the rest of the UK.
Controversially, in the Commons debate on Monday, Labour MP Stella Creasy urged the Government to exclude members of the public from any consultation on the change to the law.
On Wednesday, the Society for the Protection of Unborn Children led a cross-party delegation of MPs in delivering pro-life postcards to 10 Downing Street.
The delegation included David Simpson MP, Jim Shannon MP, Lisa Cameron MP, Sir John Hayes MP, Nigel Dodds MP and Ian Paisley MP.
Mr Dodds, the DUP's Westminster leader, said: "I am delighted to join parliamentary colleagues from across the House today to hand in the petition which has been organised by SPUC.
"I want to congratulate them on the fantastic work they're doing in order to ensure that the people who make the decisions on these vital issues about the unborn child are the elected politicians of Northern Ireland.
"They're the ones who have responsibility for this area and changes in the law should not be imposed in Westminster over the heads of the people of Northern Ireland."
SPUC's Northern Ireland Political Officer, Liam Gibson said the impending changes to the law amounted to a "dangerous imposition" of abortion on Northern Ireland that "represents the greatest tragedy for unborn babies and women".
"A hundred thousand people in Northern Ireland are alive today because Northern Ireland did not accept the same abortion law that was introduced into Britain in 1967," he said.
"The speed with which this Act was passed has made a mockery of the parliamentary process. By ramming abortion on demand down our throats Parliament has torn-up the devolution settlement and is treating Northern Ireland as a colony.
"The Prime Minister must respect the principle and spirit of devolution and ensure the people of Northern Ireland through their elected representatives get to decide on what law and policy should apply in our province.
"The Prime Minister should be focussing on re-establishing the Assembly and not trampling on the delicate political situation in Northern Ireland."