Sinn Fein's Stormont leader Michelle O'Neill said: "I will be making it very clear that any deal between the Tories and the DUP can not be allowed to undermine the Good Friday and subsequent agreements".
The Queen's Speech was originally meant to take place on Monday 19 June, but was delayed because of the governments's discussions with the DUP in order to secure a "supply and confidence" agreement.
He explained that the two parties are both committed to delivering Brexit, fighting terrorism, preserving the United Kingdom and boosting economic prosperity, giving a clue as to what will be included.
"The UK Government is offering whatever support we can, working alongside the Irish government, as appropriate, honouring our respective commitments in the Belfast Agreement to serve the interests of the whole community in Northern Ireland", he said.
Parliament's opening and the speech had been due to take place on Monday, 19 June, but were delayed by Theresa May's efforts to strike a deal with the DUP to back her minority government.
Tories have made clear since last week's election that their discussions with the DUP revolve around assurances of support in key Commons votes, rather than a full coalition.
With eight seats short of an overall majority, the co-operation from the 10 DUP members will ensure May has a majority to see through her program of measures in the next session of parliament.
Theresa May is "confident" there will be "sufficient support" in the Commons to pass the Queen's Speech.
May is due to host the leaders of all Northern Ireland's parties at Downing Street to talk about the potential implications of any deal with the DUP over power sharing at Stormont. The decision to set a firm deadline is likely to increase pressure on both parties, particularly the DUP, to reach an agreement.
Following her meeting with Mrs May, Alliance Party leader Naomi Long said the PM had "sought to give us her reassurance on neutrality".