Assembly members are set to return to the Stormont chamber for the first time in nearly three years after 31 members signed a petition triggering a recall.
The move was proposed in a last-ditch attempt to stop the reform of Northern Ireland's abortion law.
Laws on abortion and same-sex marriage in NI will change unless devolution is restored by Monday, 21 October.
So the recall will not affect the impending law changes, as it would need an executive to be appointed too.
On Thursday, the assembly Speaker Robin Newton wrote to all 90 MLAs informing them that the petition had reached the necessary 30 signatures, meaning the special sitting will take place on Monday.
The move had been proposed by Northern Ireland peer Baroness O'Loan, who opposes any reform of the current abortion law.
It was supported by campaign group Both Lives Matter, who collected the signatures from 27 DUP MLAs, Ulster Unionist leader Robin Swann and his party colleagues Robbie Butler and Roy Beggs, as well as TUV leader Jim Allister.
Confirming the target had been reached, DUP leader Arlene Foster said it will provide an opportunity for MLAs to show their opposition to the proposed law changes.
"Hopefully we will be able to debate the issue on Monday," she added.
It is not clear if MLAs will be able to debate the abortion law changes as, first, they have to elect a speaker with cross-community support.
Chris Hazzard of Sinn Féin said his party would not be present on Monday, referring to it as a "pantomime".
He told the BBC's The View programme: "Arlene Foster thinks that she is going to walk into Stormont, all of the parties are going to follow her behind, and we're all going to somehow dance to her tune.
"Sinn Féin certainly won't be playing that game."
SDLP leader Colm Eastwood said it was "clearly a stunt from the DUP".
He told the same programme: "There won't be an executive formed on Monday, it won't happen and therefore the legislation that is proposed around abortion and same-sex marriage will go through on Monday."
Also speaking on the same programme, Alliance MLA Stephen Farry said: "I'm profoundly uncomfortable that the first time people are making an effort to have the assembly reconvened is to discuss how we can deny people rights."
His party said in an earlier statement it would "use appropriate opportunities to make our point".
Steve Aiken, of the Ulster Unionist Party, said his party would attend.
"We have been calling for getting back the Assembly for over 1,000 days. We're going in," he said.
The Speaker said it was likely that the assembly would sit at 12:00 GMT on Monday, but that he would meet party whips on Friday to confirm details.
The legislation that allows Stormont to be recalled in special circumstances is rarely used.
1,000 days without devolution
Stormont's power-sharing government collapsed two-and-a-half years ago amid a bitter row about a green energy scheme and Parliament has had to pass some key legislation for Northern Ireland in the interim.
The DUP has publicly opposed Westminster legislating over the head of local ministers on abortion reform.
However, on Wednesday some questioned the timing of the party's move over the recall petition.
Other Stormont sources believe the strategy is a "mega deflection" - an attempt to move the focus on the party from Brexit to something else.
The DUP said it has consistently called for the return of Stormont.
Independent unionist MLA Claire Sugden told BBC News NI she did not sign the petition, despite speculation she was considering it.
She said it specifically related to the abortion matter, rather than the wider issue of devolution not being in place for more than 1,000 days.