Four DUP MPs still employ family members using taxpayers' money, the latest records revealed.
Sir Jeffrey Donaldson (Lagan Valley), Gregory Campbell (East Derry) and Ian Paisley (North Antrim) pay their wives for administrative roles.
Gavin Robinson (East Belfast) uses his father as a part-time office manager.
None of the 61 new MPs who secured their seats at the general election on June 8 are allowed to employ a family member.
Representatives who served in the previous Parliament were allowed to continue their existing employment arrangements with relatives.
The change was introduced by the Independent Parliamentary Standards Authority earlier this year.
Chair Ruth Evans said: "We believe that the employment of connected parties is out of step with modern employment practice, which requires fair and open recruitment to encourage diversity in the workplace."
In the past, some MPs have defended paying their spouses on the grounds that they sometimes handle confidential and very sensitive material.
In 2009, MP Derek Conway apologised "without qualification" after he was ordered to return taxpayers' money paid to his son for research while he was a student.
Campaigners have called for a clear end date for the employment of relatives.