Senator Brian Burston has denied offering to "f---" a staff member to make her feel better, as a bitter dispute erupts on the crossbench over a series of bombshell sexual harassment allegations.

Rejecting the allegation contained in a lengthy complaint sent to the Department of Finance last year and seen by The Sydney Morning Herald and The Age on Wednesday, the United Australia Party senator launched his own attack on Pauline Hanson, claiming the One Nation leader had twice sexually harassed him.

Senator Hanson denied the allegation on Wednesday night during a rushed appearance on Sky News, saying: "A lot of men have tickets on themselves and Brian Burston, don't go out in Canberra, it's very windy tonight.

"I might be 64 but I'm not that desperate. These are allegations that have been made up, there are no truth to them whatsoever and I feel sorry for his wife, I really feel sorry for his wife."