A cross-party group of backbench MPs will seek to ramp up pressure on Theresa May to decriminalise abortion in Northern Ireland on Monday, as they demand an emergency debate on the issue.

Campaigners have been pressing for the government to liberalise the abortion law there after a historic referendum in the Republic of Ireland last month backed reform, and a number of current and former ministers have expressed support.

MPs including Labour’s Stella Creasy and the Lib Dem deputy leader, Jo Swinson, hope to amend the domestic violence bill due to be tabled in parliament shortly, in a bid to repeal arcane legislation that makes abortion illegal in Northern Ireland.

They are calling for an emergency debate on Monday, which would force a government minister – most likely the women and equalities minister, Penny Mordaunt – to come to the House of Commons and explain publicly why the right to abortion should not be extended.

If a debate is granted by the Speaker, it would also reveal the scale of support among MPs for a bid to change the law.

The Offences against the Person Act (OPA) was written in 1861 and makes it a crime for any woman to cause her own abortion. The 1967 Abortion Act exempted women in England and Wales – but the restrictions continue to apply in Northern Ireland.

Creasy and her supporters believe they can force all parts of the UK to reconsider their abortion laws by repealing sections of the 1861 Act.

With the power-sharing government in Stormont suspended, the government is sensitive to claims that it would be interfering in devolved issues if it took action.

But the campaigners insist repealing the OPA would simply open the way for politicians in Northern Ireland to make their own decision about how to proceed.

The DUP leader, Arlene Foster, whose MPs back the government, has taken a robust line against decriminalisation. She told Sky News on Sunday that former Sinn Féin voters had been contacting her to say they had switched support to her party over the issue.

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“I have had emails from nationalists and republicans in Northern Ireland not quite believing what is going on and saying they will be voting for the DUP because they believe we are the only party that supports the unborn.”

Foster also criticised the celebrations in the Republic of Ireland after voters overwhelmingly backed reform in last month’s referendum, saying she found it “quite distasteful to see people dancing about on the streets”.

Some Conservative MPs sympathetic to the cause of liberalising abortion rules in the province believe a referendum should first be held to gauge public opinion. “They need to have a referendum – now,” said Anna Soubry.

But critics warn that could open the way for other highly contentious issues to be settled in the same way.

Sinn Féin responded to last month’s referendum result by pressing its case for a referendum on a united Ireland. “I think in terms of the conversation at home now it’s very much about a union referendum, it’s very much about the constitutional future,” the party’s vice president, Michelle O’Neill, said.

The Tory deputy chairman, James Cleverly, claimed last week the bid to amend the domestic violence bill had “little to do with women’s right to choose, and everything to do with opportunistic party political game playing”.