The Sinn Féin leader Mary Lou McDonald has said she is "absolutely convinced" that a deal can be reached with the DUP to restore power-sharing in the North.
Talks to get the Stormont assembly back up and running began last week, after more than two years since it sat following a row between both parties.
Ms McDonald and the British Prime Minister Theresa May are set to talk by phone on Monday.
Speaking ahead of the call, Ms McDonald said: "Sinn Féin has entered these to resolve the outstanding issues, secure rights for all citizens, and to re-establish the power sharing institutions operating to the highest standards.
"The issues outstanding are not intractable. They can and must be resolved.
"Delivering good governance, the implementation of existing agreements and securing the rights enjoyed by citizens in the rest of Ireland is long overdue and will benefit all and disadvantage none."
"The two governments are not spectators or referees in this process, they are co-equal guarantors of the people's agreements and rights.
"The actions of the British government, their deal with the DUP, imposition of Brexit and refusal to honour their obligations on the legacy issues of the past, has dogged this process for the last two years.
"I will be raising these issues directly with the British Prime Minister on Monday. I believe an agreement can be reached and genuine power sharing can be established."
"It will require the British government to live up to its obligations under the Good Friday Agreement, to be rigorously impartial and to put the rights and equality of citizens above any short term party political concern," she added.
Ms McDonald said she is upbeat on the prospect of finding a solution that works for both sides.
"I am absolutely convinced that these issues can be resolved - I'm convinced of that because we managed to land on an accommodation before.
"Unfortunately at that time, we didn't have a partner in unionism to deliver that deal: I very, very much hope that this time round we can not alone strike a deal, but that we can find partners in unionism".
She added that understanding and equality is needed for the talks to succeed.
"For power sharing to work, it has to work on the basis of equality - that's the only way that it'll be sustainable.
"Good government in the North has to be government that's based on a shared understanding that we have to make room for everybody".