Caroline Noakes has called for Nadhim Zahawi to step aside as Conservative Party chairman while the investigation into his tax affairs takes place.
Ms Nokes, chair of the women and equalities committee, said Mr Zahawi should “temporarily” stand down during the investigation.
She added that “for his own sake” he should “allow some space” between the probe and his chairman role, as part of which he attends cabinet.
The MP also urged him to “come clean on all of the questions being posed” into his affairs.
Opposition parties have called on Mr Zahawi to resign immediately, with Labour leader Sir Keir Starmer calling his position “untenable”.
Shadow foreign secretary David Lammy said on Tuesday he was becoming a “huge distraction” for the government from the cost of living, strikes and the state of the NHS.