More than 15,000 people in Northern Ireland have signed a letter opposing a new law to liberalise abortion.

British MPs have said the legislation - and the introduction of same-sex marriage - should happen unless the Assembly at Stormont is restored by 21 October.

The signatures were included in a letter to British Prime Minister Theresa May calling for politicians and the public in the North to be consulted before any changes are made to abortion legislation.

The two largest parties, the DUP and Sinn Féin, are on opposite sides, with unionists firmly opposed to any change.

The amendments to a Northern Ireland Bill were tabled by Labour MPs Stella Creasy and Conor McGinn.

As the law stands in the North, abortion is available only in very limited circumstances and same-sex marriage remains illegal.

The letter to Mrs May was written by ex-police ombudsman Nuala O'Loan and Robin Eames, the former Church of Ireland primate, in support of an amendment laid down at the House of Lords debate on the Bill.

The changes were introduced as amendments to a law that delays elections in Northern Ireland to 21 October and potentially 13 January 2020, to allow further power-sharing talks.

The abortion amendment, which passed by 332 votes to 99, directs the British government to implement recommendations of a report published last year.

It said the law criminalising abortion should be repealed and the procedure legalised at least where the mother's health is at threat, in cases of rape or incest or severe foetal impairment.

The other amendment, passed by 383 votes to 73, requires the British government to introduce regulations "to provide that marriage between same-sex couples is lawful" in Northern Ireland.

The legislation must still be approved by the unelected upper House of Lords.

Director of Evangelical Alliance in the North Peter Lynas said Christians and those without faith oppose changes to abortion laws.

"Abortion is one of the most sensitive political, moral and social issues of our time, especially in Northern Ireland where it is a devolved matter," he said.

"We object strongly to what happened last week, both in terms of the process and the substance of the motions passed."

However Grainne Teggart, campaigns manager for Amnesty UK in the North, said recent opinion polls indicate people in the North want to see abortion laws changed.

"Successive opinion polls and studies have consistently shown that the majority of the Northern Irish public are in favour of abortion law reform, including decriminalisation," she said.

"A recent poll commissioned by Amnesty demonstrates that 66% want to see Westminster legislate for change in the absence of devolved government. In a recent Northern Ireland Life & Times Survey, 70% of the public said they are pro-choice.

"The vote in the Commons last week reflects the will of the Northern Ireland public and it is right that Westminster brings about long overdue change," she added.

Talks aimed at trying to restore the Stormont Assembly resume this week. Expectations of success are not high.

Additional reporting Vincent Kearney