The DUP has been urged to grasp the goodwill being shown to Northern Ireland during the Good Friday Agreement commemorations and restore the power-sharing institutions at Stormont.
Sinn Féin MP John Finucane said the executive needed to come together to speak with a united voice to the Treasury about budget difficulties in the region.
But DUP MLA Emma Little-Pengelly said that power-sharing could only be restored on the “right foundations” and added that action by the UK Government was needed to bring Stormont back.
The remarks come ahead of an address by British prime minister Rishi Sunak to close a major three-day conference to mark the 25th anniversary of the 1998 peace accord which largely brought an end to the Troubles in Northern Ireland.
The event at Queen’s University Belfast has seen political leaders fly in from across the world, including former US president Bill Clinton, ex-prime minister Sir Tony Blair, former taoiseach Bertie Ahern and European Commission vice president Maros Sefcovic.
Taoiseach Leo Varadkar and European Commission President Ursula von der Leyen will also address the conference on Wednesday.
While celebrating the achievement of the 1998 accord, the conference has also seen repeated words of encouragement to restore the Stormont Assembly, which has been collapsed for the last year amid a DUP boycott over post-Brexit trading arrangements.
Mr Finucane told the BBC Good Morning Ulster programme that he wanted to see the democratic outcome of last year’s Assembly elections, in which Sinn Féin emerged as the largest party, respected.
He said: “The DUP should move to enable power-sharing to take place, they should prioritise the needs of those who are on the waiting lists, children who have had access to holiday meals removed, and grasp the opportunity, because that is something that has also shone through powerfully over the last two days, the enormous positivity and goodwill that we have been presented with to allow our economy to progress and flourish and to deliver for everyone in our society.”
Mr Finucane was asked about a leaked Northern Ireland Office briefing paper which recommends revenue-raising measures such as water charges and higher tuition fees should be the focus of future Stormont budgets.
He said: “The key in this is the need for a restored executive because nobody is under any illusions that there are very tough decisions to be made.
“The need for all of that requires an executive and that united voice going to the British treasury and asking for the funds that are necessary.”
But Ms Little-Pengelly said the issues which caused the collapse of the Stormont institutions have still not been fully addressed.
“I think it is important that we put across our position, we have been very clear that we want to see devolution restored, but it has to be restored on the right foundations,” she told the BBC Nolan Show.
She added: “We need to address what it was that broke this in the first place.
“The Secretary of State (Chris Heaton-Harris) knows that, he knows what needs to be done.
“Quite frankly, making speeches and having digs is not going to resolve this, what is going to resolve it is talking with each other, it is action by the UK Government, there is a pathway to getting Stormont back.
“Our plea to everybody is to get on with that.”
The UK government insists the DUP concerns have been addressed by the new trading deal it struck with the EU, the Windsor Framework.
But Northern Ireland’s largest unionist party has insisted the UK government needs to provide it with further legal assurances on sovereignty and the application of EU law in Northern Ireland.
The final day of the Belfast conference will see Mr Sunak vow to “give everything” to deliver the vision of sustained economic growth and tackle the problems of a divided society in Northern Ireland.
Mr Sunak will then later host a gala dinner, attended by political leaders, international dignitaries and leading charities.
