Carrie Johnson is said to have openly questioned Chris Pincher's suitability as a Government whip back five years ago, according to reports.
The then-communications director of the Conservative Party was said to have sent messages asking how the MP ended up in the whips' office.
The exchanges, Sky News say they have seen, came after he resigned as a whip in 2017 following claims of unwanted sexual advances to a Tory candidate.