SINN Fein has outlined details of a draft agreement it insists it struck with the Democratic Unionists before negotiations to restore Stormont power-sharing collapsed.

Accusing the DUP of pulling the plug on the deal, Sinn Fein president Mary Lou McDonald said she needed to dispel “mistruths and inaccuracies” about what it contained.

She said the deal resolved the thorny language issue at the heart of the Stormont impasse with three separate pieces of legislation – an Irish Language Act, an Ulster Scots Act and an overarching Respecting Language and Diversity Act. McDonald said no consensus was reached on the region’s ban on same-sex marriage.

She said the text included a review of the Assembly’s contentious voting mechanism – the Petition of Concern – and the establishment of a committee to look at the potential of drawing up a Bill of Rights for Northern Ireland.

McDonald said the two parties had also secured a commitment from the UK Government to commence a public consultation on stalled mechanisms to deal with the Troubles and to release funds needed to finance legacy inquests.

She said the parties also agreed that the Stormont Executive’s sensitive justice ministry would start to be allocated in a conventional manner from 2022, rather than being a jointly agreed DUP/Sinn Fein nomination.

McDonald said the “draft agreement” was struck late last week.

“At that time we advised the DUP leadership that the deal should be closed before those opposed to it could unpick what we had achieved,” said the Sinn Fein leader.

“We made it clear that if there was a delay there was every chance that the package would unravel. The DUP failed to close the deal, and went on to collapse the talks process.”

Meanwhile, Social Democratic and Labour Party Leader Colum Eastwood urged the Irish Government to press for the formation of the British Irish Intergovernmental Conference to chart the way forward for Northern Ireland in the absence of devolution.

The conference is a peace process construct designed to give the Irish Government a consultative role in the UK Government’s handling of non-devolved issues in Northern Ireland. It was last convened in 2007, before the historic DUP/Sinn Fein powersharing deal of later that year.

Eastwood said: “It is important for all of us to understand that this isn’t just one more turn in the cycle of failure which has now gone on for the last 13 months. Instead all of us are being faced with the prospect that the cycle of negotiations now ends and that power is handed over to a Tory/DUP Government in Westminster.

“We are being faced with the prospect and threat that all decisions on the governance of Northern Ireland are to be made by a Tory/DUP committee in London.

“That scenario is cause for deep concern and worry, particularly for northern nationalism which has been left powerless after this failed negotiation. It is a scenario which runs against everything imagined, won and endorsed in the Good Friday Agreement. It is a scenario that only rewards the DUP.”

The Foyle MLA added: “In the absence of ongoing negotiation to restore devolution, I have said that the first step must be the formation of the British Irish Intergovernmental Conference. That is the first step outlined in the Good Friday Agreement – there is no logic or reason why that should be resisted.”