The Northern Ireland Assembly has been recalled in an attempt to restore the devolved power-sharing institutions.
The DUP is expected to once again block the election of an Assembly speaker during Wednesday's plenary session.
The Assembly cannot operate business as usual without a speaker in place.
The SDLP successfully gained support for a recall petition to nominate a speaker from the Alliance Party and Sinn Féin.
It said the recall would serve as a challenge to the DUP to get back to work.
In February, the DUP withdrew its first minister from the executive due to concerns over the Northern Ireland Protocol, and since the election in May, the party has refused to re-enter power sharing.
The protocol a trade deal which was agreed between the UK and EU as part of Brexit.
Last week, DUP leader Sir Jeffrey Donaldson said he wanted to see “clarity and certainty” from a new prime minister on their approach to the protocol before making further decisions.
Two previous attempts to elect a speaker, which would open the way for the nomination of First and deputy First Ministers, have failed.
A motion to debate the cost-of-living crisis has also been scheduled for the Assembly session on Wednesday, but this won't proceed without the a speaker being elected.
The SDLP's Stormont leader Matthew O'Toole said it was "outrageously cruel" for Stormont not to be functioning at a time when families were struggling with rising prices.
He said: "Since the Assembly last met, the crisis facing families and households across Northern Ireland has deepened.
"Energy prices are spiraling, fuel costs are prohibitively high and thousands are now facing the additional burden of back-to-school costs with no additional support from the people they elected three months ago on a promise to help.
"The challenge that the SDLP opposition will make to the DUP is simple - get back to work or explain yourselves to the thousands of families who have been held to ransom for the last 90 days.
"The excuses about the Northern Ireland Protocol Bill have evaporated now that the legislation has passed its Commons stages.
"Continuing to deny people urgent support is unethical, immoral and outrageously cruel."
Ulster Unionist MLA Mike Nesbitt has been nominated for the role of speaker on the previous two occasions when the Assembly was recalled.
He said he did not believe Wednesday's recall would achieve anything while there were still outstanding differences over the protocol.
"It's not going to go anywhere. Everybody knows it's not going to go anywhere. So we question the point of doing this," he said.
"I think what would be better than a show, a public show in that chamber, is party leaders getting together quietly, privately, and trying to resolve the differences.
"We have challenges. We don't have crises at the moment. Let's deal with the challenges."
The recalled sitting of the Assembly was originally due to take place last week but was postponed following the death of Lord Trimble, one of the key architects of the 1998 Belfast/Good Friday Agreement.
Mr Nesbitt said: "There is only one fitting tribute to David Trimble and that is for all of us here at Stormont to get the institutions back up and running again, to deal with the issues including the protocol and to deal with everything that we have to deal with.
"What we are dealing with are challenges but they're nothing like what David Trimble had to overcome 25 years ago."
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