Northern Ireland’s political leaders have clashed just days away from fresh Stormont Assembly elections.

Challenged to say whether they will form an Executive or refuse to accept their salaries if re-elected, DUP leader Sir Jeffrey Donaldson reiterated his position that he will turn up on day one after the election, but will not form an Executive until concerns around the Northern Ireland Protocol are dealt with.

He said the political institutions “must be sustainable”.

Sinn Fein vice president Michelle O’Neill said it would be “absolutely unfathomable” to tell the electorate that a new Executive would not be formed following the election.

She also said she still has not heard if unionist leaders will “accept the democratic outcome of the election”, in a seeming reference to opinion polls which suggest Sinn Fein will become the biggest party at Stormont and entitled to nominate a first minister.

Sir Jeffrey has not said if he will nominate a deputy first minister to serve along with a Sinn Fein first minister in the joint office.

Ms O’Neill accused the DUP of “holding us all to ransom” over its position on refusing to go back into an Executive without action on the Northern Ireland Protocol.

The resignation of First Minister Paul Givan in February left the Executive unable to fully function.

“Whilst the rest of us want to put money in the people’s pockets and deal with the cost-of-living crisis, the DUP are telling people their identity is under threat,” Ms O’Neill said.

Sir Jeffrey responded, pointing to the resignation of former deputy first minister Martin McGuinness which saw the Assembly collapse for three years.He said ministers continue in their posts, while Ms O’Neill countered saying they are “caretaker ministers”.

The leaders of the five largest parties took part in a live debate on BBC One Northern Ireland on Tuesday evening ahead of polling day on Thursday.

SDLP leader Colum Eastwood said while they can talk about the cost-of-living crisis and the health services, “nothing will be done about any of these issues if we don’t have a government”.

He said government in Northern Ireland cannot be stopped because the UK government and the European Commission have not reached an agreement over the protocol.

UUP leader Doug Beattie said he wants to see a programme for government agreed before a new Executive is formed.

“If you agree the programme for government first, its outcomes, what the budget is going to be… I think that’s an important way for us to travel,” he said.

Alliance leader Naomi Long said she will also be in Stormont ready to form an Executive if she is returned by the electorate.

She urged that MLAs are “not locked out”, adding she does not want the “embarrassment” of being paid her full salary as an MLA while the Assembly is not fully functioning.

Asked about a border poll, Sir Jeffrey said he did not want one, saying it would be divisive.

Ms O’Neill said she is “not fixated” on a date for a future border poll, describing the cost-of-living crisis as the big issue at present.

Mr Eastwood said the lack of government at Stormont is today’s issue, not a border poll while Ms Long said her party will not be calling for a border poll, and instead focus on doing government.

Mr Beattie insisted a border poll is not close, and claimed the DUP are using the prospect of a border poll as “scare tactics”.

Voters will go to the polls on Thursday to elect 90 MLAs for 18 constituencies across Northern Ireland.

Results are expected to become known from Friday following the counting of the votes.