A group of Northern Irish lawmakers will return to their parliament on Monday in a last-minute protest at the liberalisation of abortion laws, set to come into force after being decided by London for the suspended Belfast executive.

It will be the first time the regional government in Belfast will have sat in three years.

It collapsed in January 2017 after a scandal over a renewable heating scheme split the power-sharing executive, amid a breakdown in trust. The province has been without a government since the breakdown.

Abortion is currently illegal in Northern Ireland, except when the mother’s life is in danger.

With the Northern Ireland Assembly not sitting, the British government in July passed legislation forcing the province’s laws on abortion and same-sex marriage, which is also illegal, into line with those in the rest of the UK – unless the executive returns by Monday.

However, the return of around 30 of the 90 Northern Ireland Assembly members specifically to discuss abortion law is expected to be symbolic.

The majority of those appearing at Stormont will be members of the conservative Democratic Unionist Party (DUP), led by Arlene Foster.

But without cross-party support, a first minister and deputy first minister cannot be elected – the assembly’s first task – meaning the law cannot be blocked.

Michelle O’Neill, the left-wing Sinn Fein party’s leader in Northern Ireland, described the event as “stunt politics”.

“They’re going to discuss issues which they can do nothing about. For me, that’s all about being dishonest with the public,” she said.

“We want to be in the assembly but we need to get the issues resolved that brought the assembly down.”

Trevor Lunn, an assembly member for the centrist cross-community Alliance party called the bid to recall the assembly “showboating”.

“It appears those wanting to go back on Monday are only doing so to try and deny LGBTQ people and women the rights guaranteed to them in the rest of the UK,” he said last week.

Celebrations are due in the province to herald the changes in the law.

Campaign group Love Equality said couples and supporters will gather in Belfast ahead of Monday’s midnight deadline.

A mock-wedding event with “a buffet reception, speeches and photo opportunities featuring a wedding cake, flowers and balloons” will take place at lunchtime, the group said in a statement.

Meanwhile, the Women’s Resource and Development Agency campaign group is also organising a protest at Stormont against the bid to block the new legislation.

Pro-life group Both Lives Matter said 31 assembly members have signed the recall petition allowing parliament to sit on Monday.

Foster told the BBC the move will allow deputies to express opposition to the law changes.

“Hopefully we will be able to debate the issue on Monday,” she said.