Labor leader Bill Shorten has weighed into the internal ALP battle over the replacement for former senator Stephen Conroy by backing one of his closest friends, controversial lawyer Kimberley Kitching, to fill the breach.

The new senator will effectively be ratified tonight when the party's public office selection committee votes on candidates, with an agreement across sub-factions that the candidate should be a woman.

Kimberley Kitching. Credit:Eddie Jim

Ms Kitching, the wife of notorious former political blogger Andrew Landeryou, would be a contentious choice, with senior party figures warning of the dangers of her preselection to the party and Shorten.

"It's crazy" is one how one federal Labor frontbencher described the Shorten push for Ms Kitching.