Prime Minister Scott Morrison has championed Dave Sharma as the Liberal party's "best candidate" for the seat of Wentworth, brushing aside suggestions he was rolled in his preference to have a woman contest the seat.

Mr Morrison lavished Mr Sharma with praise and congratulated preselectors for "picking the best person for the job", as he launched Mr Sharma's byelection campaign for the historically blue ribbon seat in Bronte on Friday morning.

"They've made a great pick," Mr Morrison said. "He's is one of the few blokes who can walk into the room and pretty much be the smartest person in the room."

Just 24 hours earlier, factional lieutenants were encouraging Mr Sharma to withdraw from the preselection race after Mr Morrison indicated he wanted a woman in the seat, and was backing Mr Sharma's key rival Katherine O'Regan.