A Democratic Unionist MP is facing calls to quit after a watchdog recommended his suspension from the House of Commons for failing to register two family holidays funded by the Sri Lankan government.

Ian Paisley had already apologised for what he said was his “unintentional failure” to register the hospitality, which he estimated was worth £50,000.

Politicians from across the political divide in Northern Ireland have called on the high-profile MP to stand down.

The 30-day suspension recommended by a parliamentary watchdog on Wednesday could force Mr Paisley to face a by-election.

Members who are suspended from the Commons for more than 10 days are open to a recall petition.

A by-election would be triggered if 10% of the electorate in Mr Paisley’s North Antrim constituency sign that petition.

If rubber stamped by Parliament, the suspension will also mean Prime Minister Theresa May will be shorn of one of the 10 DUP MPs propping up her minority government during a period that could see a number of crucial Brexit votes in the House of Commons.

Sinn Fein president Mary Lou McDonald said Mr Paisley should do the “honourable thing” and quit.

“I think the charges made against him and findings against him are very serious,” she said.

“I would imagine his constituents in North Antrim, and certainly public opinion across Ireland, would expect that having been sanctioned in the way he’s been sanctioned then he should do the honourable thing and step down.”

The SDLP said Mr Paisley’s position was “untenable”.

Party Assembly member Colin McGrath said a 30-day suspension was not enough.

“The SDLP will be seeking a recall petition to dismiss Paisley from Westminster, and should this trigger a by-election in North Antrim, Mr Paisley should not challenge the seat again,” he said.

Alliance Assembly member Paula Bradshaw also urged Mr Paisley to consider his position.

“Mr Paisley has let both himself and his constituents down, calling into question his personal integrity and the ability of voters to trust him,” she said.

Leader of the Traditional Unionist Voice party Jim Allister called on Mr Paisley to refund the Sri Lankan government the money it spent on hosting him, accusing the MP of “serious and shameful” breaches of Parliament’s code of conduct.

The sanction was outlined by the House of Commons Standards Committee following receipt of the findings of an investigation by the Parliamentary Commissioner for Standards.

The committee said Mr Paisley, son of late DUP founder the Rev Ian Paisley, had committed “serious misconduct” and his actions “were of a nature to bring the House of Commons into disrepute”.

The report, which said the cost of the hospitality may have been “significantly more” than Mr Paisley’s £50,000 estimate, said the Sri Lankan holidays in 2013 included business-class air travel, accommodation at first-class hotels, helicopter trips and visits to tourist attractions for the North Antrim MP and his wider family.

The trips also included meeting with Sri Lankan governmental figures.

The threshold for registering such hospitality in 2013 was around £660.

In March 2014, Mr Paisley wrote to the then prime minister David Cameron to lobby against a proposed United Nations resolution setting up an international investigation into alleged human rights abuses in Sri Lanka.

The committee noted that in his letter, the MP did not declare the financial benefits he and his family had received from the Sri Lankan government during the previous 12 months.

Amnesty International Northern Ireland director Patrick Corrigan said: “The real outrage at the heart of this scandal is an MP attempting to have the United Kingdom government oppose a United Nations investigation into the horrific war crimes committed in Sri Lanka.”

The watchdog also recommended that Mr Paisley should now register the holidays with the parliamentary authorities.

The recommendations will need to be approved by the House of Commons before being confirmed.

Mr Paisley is due to address the House on Thursday.

The story was first reported by The Daily Telegraph in September 2017, in a report which estimated the cost of the hospitality at £100,000.

A statement issued by Mr Paisley’s lawyer on Thursday said: “My client has apologised unreservedly at the outset for his unintentional failure to register the hospitality he received.

“While accepting the decision of the House Standards Committee, he nonetheless continues to take issue with the sensationalised report in the Daily Telegraph.

“Legal proceedings are being considered.

“No further comment will be made until Mr Paisley has addressed the House on Thursday.”

A DUP spokesman said: “The party has noted the House of Commons Standards Committee’s report on Ian Paisley MP. These matters will now be considered by the party officers.”