The UK Government should legalise same-sex marriage in the absence of Stormont power-sharing, Lyra McKee's partner has said.
Sara Canning will address a rally calling for change in Northern Ireland at Belfast City Hall tomorrow.
Ms McKee, 29, was shot in the head by dissident republican group the New IRA during clashes with police in the Creggan estate in Derry last month.
Organisers predicted large numbers would march in Belfast tomorrow for what they termed marriage equality.
Same-sex marriage is not allowed in Northern Ireland, although civil partnerships are recognised.
Fresh Stormont political talks were kick-started by Ms McKee's death.
Ms Canning said: "Lyra and I wanted to get married, surrounded by our families and friends, because we shared a love which meant we wanted to spend the rest of our lives together.
She added: "With Stormont out of action for almost the last two and a half years, we need the UK Government to step in.
"That's what I told Theresa May at Lyra's funeral and that's what I will be saying at the march for marriage equality in Belfast.
"I hope the Prime Minister is listening. Couples like Lyra and I should not have to wait a day longer for the law to recognise us as equals."
The ban is one of the disputes at the heart of the power-sharing impasse in Belfast, with the DUP resisting Sinn Fein calls for a law change.
The socially conservative DUP is firmly opposed to any redefinition of the law, insisting marriage should be between a man and a woman.
A majority of Stormont members were in favour of lifting the prohibition when the issue last came to the floor of the chamber but the DUP triggered a contentious voting mechanism - the petition of concern - to block it.