SINN Féin MP John Finucane is to amend his register of interests amid criticism as it suggests he still works full-time for his law firm.
For the past six months the North Belfast MP's register of financial interests has said he has an "expected commitment of 40 hours a week" at Finucane Toner.
The solicitor remains a director of the firm and is paid £4,672 a month, according to the details first lodged with Westminster officials back in January.
In February, Sinn Féin said the register was "outdated and inaccurate" and insisted Mr Finucane remains "focused on his role as an MP".
However, under the MPs' code of conduct, members must register any change to their registrable interests within 28 days.
These rules apply regardless of whether MPs take their seats or not.
Mr Finucane ousted Brexiteer DUP deputy leader Nigel Dodds in last December's election, benefitting from added pro-Remain support after the SDLP and Greens stood aside.
Sinn Féin MPs do not take their seats at Westminster due to the party's abstentionist policy.
DUP North Belfast MLA Paula Bradley accused Sinn Féin of double standards.
"Either John Finucane is continuing to work 40 hours per week in his law firm, or he has failed to properly update the register of interests as is demanded of him and every other MP," she said.
"This appears to be another example of Sinn Féin's 'do as I say, not as I do' attitude. They are vociferous when it comes to other representatives registering outside interests, but yet again they appear to believe the standards they demand of others should not apply to them."
UUP councillor Robert Foster also said Mr Finucane "has already been approached about this before", adding: "It doesn't say a lot for the first excuse which Sinn Féin provided back in February."
Criticising Sinn Féin's abstentionist policy, he added: "I don't see why the taxpayer should be subsiding the expenses for Sinn Féin's part-time MPs."
Sinn Féin defended the submission in Mr Finucane's register of interests.
However, the party said it would be amended "for the avoidance of doubt" to show an "expected commitment of 10-20 hours per week" at Finucane Toner.
A party spokesman said: "When registering his interests Mr Finucane declared an 'expected commitment' of 40 hours per week with Finucane Toner Ltd, not a guaranteed commitment of 40 hours per week.
"As has been stated in February, the expectation that Mr Finucane would work 40 hours per week was 'outdated and inaccurate'.
"For the avoidance of doubt, the registry has been updated to indicate an expected commitment of 10-20 hours per week to Finucane Toner which, if utilised, would be accommodated around his primary role as MP for North Belfast.
"Mr Finucane has at all times complied with his obligations to the register of interests."
