Four DUP politicians failed to make complete donation reports about a trip to Israel, BBC News NI has learned.
Six DUP MPs reported receiving donations of £2,700 from NI Friends of Israel to pay for the four-day visit in May, the electoral watchdog confirmed.
But while four DUP MLAs reported donations to the Assembly, they did not report them to the Electoral Commission within the required 30 days.
The DUP said steps had been taken to rectify an "administrative oversight".
"The trip was declared on the Assembly register of interests," said a spokesman.
The visit - which cost £2,700 per delegate - was funded by the lobbying group Northern Ireland Friends of Israel, with extra costs being met by the Israeli Ministry of Foreign Affairs.
The DUP said the visit was "aimed at developing economic links in such sectors as cyber security, with Israeli and Northern Ireland companies at the cutting edge of new technology in this specialist field".
The four Members of the Legislative Assembly (MLA) on the trip were:
- Gary Middleton - Foyle
- William Humphrey - North Belfast
- Michelle McIlveen - Strangford
- Jonathan Buckley - Upper Bann
The latest developments come after it emerged that DUP MP Ian Paisley failed to declare two family holidays paid for by the Sri Lankan government.
MPs voted last week to suspend Mr Paisley from the House of Commons for 30 working days and he was suspended by the DUP "pending further investigation into his conduct".
Herzog grave visit
Mr Paisley was one of six MPs who travelled to Israel with the MLAs for the trip.
The other MPs were DUP Deputy leader Nigel Dodds, Jeffrey Donaldson, Emma Little Pengelly, Gregory Campbell and Paul Girvan, all of whose donations were recorded properly.
Donations from NI Friends of Israel worth £2,700 to each of the six MPs were published on the commission's website.
Different rules for reporting donations
Legislation was passed at Westminster in March requiring donations to parties and politicians from Northern Ireland to be published.
- MPs must report any donations they receive to the Parliamentary Commissioner for Standards
- This information is passed to the Electoral Commission which publishes the details on its website
- The rules are different for MLAs, who must report any donations to both the Register of Members' Interests at the NI Assembly and the Electoral Commission
Electoral Commission rules state MLAs must report all donations of more than £1,500 to the commission within 30 days.
"We have already written to these MLAs to clarify why no return has been made," said an Electoral Commission spokesman.
End of Twitter post by @little_pengelly
The DUP said it was in the process of rectifying the situation, and suggested the reporting procedures should be reviewed.
"Thought should be given to updating the Assembly procedures so they are aligned with the processes in Westminster," said a spokesman.
During the visit the DUP politicians met Israeli opposition leader Isaac Herzog, as well as former Palestinian Authority Foreign Minister Dr Nabil Shaath.
They also visited the grave of Chaim Herzog, the former Israeli president who was born in Belfast 100 years ago.