It's been claimed an average of 28 women a week travel from Northern Ireland to England for an abortion.
Figures from the British Pregnancy Advisory Service, obtained by Labour MP Stella Creasy, suggest 342 women crossed the Irish Sea between March and May this year. Official government figures show that 833 women travelled to England or Wales for an abortion in 2015.
On Sunday more than 170 politicians from across the spectrum in the UK and Ireland called on the British Government to reform Northern Ireland's abortion laws
The group, including Conservative, Labour and Lib Dem MPs and peers, Stormont Assembly members and Irish TDs and senators, said it is a matter of protecting women's human rights and honouring the Good Friday Agreement.
According to the group, nearly 1,000 women and girls were forced to travel to Britain for safe terminations in 2017, while others had to take illegal abortion drugs at home.
Calls for Northern Ireland's abortion laws to be reformed have intensified after a referendum in the Republic of Ireland resoundingly backed liberalising legislation south of the border.
Downing Street has previously said abortion law is a devolved issue, however the absence of a power-sharing agreement at Stormont has placed pressure on Westminster to act.
Prime Minister Theresa May's allies in the DUP, on whom she relies for her Commons majority, are staunchly opposed to relaxing abortion laws.
In a letter to the Sunday Times, the group has urged the UK Government to repeal sections 58 and 59 of the Offences Against the Person Act 1861 that makes it a crime for a woman to cause her own abortion in Northern Ireland.
They wrote: "This is the first and critical step to ending the treatment of British and Irish women living in Northern Ireland as second-class citizens, who do not enjoy the same access to healthcare as their counterparts do across these islands.
"We therefore call for our respective governments to act to ensure that the spirit of the Good Friday Agreement is upheld and the human rights of the women living in Northern Ireland are respected."
Conservatives Sarah Wollaston, the chairwoman of the Commons Health and Social Care Committee, former women and equalities minister Nicky Morgan and former party chairwoman Baroness Warsi were among nine Tory MPs and peers to back the calls.
Sinn Fein leaders, Michelle O'Neil and Mary Lou McDonald also signed the letter, along with Fine Gael Senator Catherine Noone, who chaired a committee that recommended changing the law in the Republic.
Labour deputy leader Tom Watson, Lib Dem deputy Jo Swinson and Home Affairs Select Committee chairwoman Yvette Cooper also provided cross-party support to the call.