Sir Jeffrey Donaldson has left open the possibility that the DUP will block the election of a new Speaker when the Stormont Assembly meets on Friday.
The DUP leader said on Wednesday that his party had yet to make a decision on whether to vote to elect a new Speaker when MLAs meet in the chamber in two days’ time.
The election of the new Speaker is the first item on the agenda for MLAs following the election and requires cross-community support from nationalist and unionist members.
The DUP is refusing to return to the power-sharing Executive until its issues with the Northern Ireland Protocol are resolved.
Sir Jeffrey told BBC Radio Ulster that his party would decide by Friday whether to elect a new Speaker.
He said: “We will be there on Friday. Our members will be there to sign the roll. We will make a decision as to how we proceed. We’ll get the group together and we’ll determine how best to take this forward.
“I’m waiting to see what the Government has to say. So, that is the priority right now, to ensure that what the Government say is moving us in the right direction.
“I’m simply saying that we will need to make a decision on that. That’s one of the decisions we’ve got to make.”
Foreign Secretary Liz Truss is set to tell the EU that the dispute over Northern Ireland cannot drag on, amid concerns in EU capitals the UK is poised to take unilateral action on the post-Brexit arrangements in the region.
Sir Jeffrey said on Tuesday he would not leave the House of Commons to take up his seat in the Northern Ireland Assembly until issues around the protocol are resolved.
On Wednesday, he stressed there was “unfinished business” at Westminster.
“If the Government are going to act, then I believe, as the unionist leader, I need to be here to see that through because it’s fundamentally important.
“There isn’t a single Unionist Member of the Assembly elected last week who supports the protocol. We can’t go on with that kind of situation.”
He also said he did not anticipate any DUP candidate who failed to secure a seat in the Assembly would be co-opted to represent Lagan Valley while he remains at Westminster.
He said the seat would not remain “vacant” and that an announcement on his temporary replacement would be made in the coming days.
