The first same-sex marriages are expected to take in place in Northern Ireland around Valentine's Day.
However, it will be further into 2020 before women can access pregnancy termination services.
Abortion and same-sex marriage were both legalised in the North at midnight last night.
The changes were enforced from Westminster in the absence of a sitting executive at Stormont.
Legislation allowing for same-sex marriage will be finalised by early January – with the first union expected around by February.
Meanwhile, laws criminalising abortion have now lapsed with legislation allowing for terminations expected to be complete by April.
In the meantime, women will be offered free transport to access services in England.
Amnesty International spokesperson Grainne Teggart said there is a lot of work to be done before the legal changes are finalised.
“Regulations have to be put in place by January 10th so therefore we expect the first same-sex marriages to take place on or around Valentines’ Day,” she said.
“Equally, for abortion access here, what we will now see is a short consultation period of eight to ten weeks where there will be regulations put in place that will govern abortion access here.
“That has to be done by the March 31st 2020.”
Meanwhile, the Catholic bishops of Northern Ireland have described the repeal of the abortion ban as 'a tragic day for unborn children.'
DUP leader Arlene Foster described the reforms as 'sad' and 'shameful.'
Sinn Fein’s leader in the North Michelle O'Neill said the changes marked a “huge step forward” for LGBT+ and workers’ rights.
She paid tribute to the campaigners that helped bring about the change.
As of midnight, the North has taken a huge step forward in LGBT+ and women's rights.
I want to commend all those that have campaigned over the decades for these fundamental rights.
Let's continue to build an inclusive and just society that cherishes all its citizens equally. pic.twitter.com/ALz9YQjE93
— Michelle O’Neill (@moneillsf) October 21, 2019
“I send solidarity to all those people that have been actively out on the ground campaigning for rights to be delivered to all sections of our society,” she said.
“Solidarity to all those activists that have worked so hard to deliver marriage equality to all those people who just wanted to get married and to have that recognised in law.”
The changes came despite a last-ditch attempt to recall the Stormont Assembly and block the changes from 31 unionist MLAs.
The MLAs held a sitting at Stormont yesterday afternoon; however, they were unable to prevent the changes going through as they did not have the numbers needed to appoint an Executive.
"If the DUP applied the same creativity and imagination into getting the institutions up and running as they have in denying rights we would have a functioning Assembly" @moneillsf speaking at Stormont today #Brexit pic.twitter.com/KFIU5vohlm
— Sinn Féin (@sinnfeinireland) October 21, 2019