Labor WA candidate has assault conviction

Labor has defended the preselection of a union boss who has a prior conviction for assault.

Joe Bullock is Labor's No.1 candidate in the West Australian Senate election re-run this Saturday.

The WA state secretary of the Shop Distributive and Allied Employees Association was convicted in Perth Magistrates Court of unlawful assault in November 1996 over an incident six months earlier.

Labor frontbencher Brendan O'Connor said Mr Bullock was the preselected candidate and should be elected to stand up for workers in WA.

"It's important that people focus on the real issues here and not be distracted by those matters," Mr O'Connor told reporters in Melbourne on Thursday.

"He has been preselected. He is a good man and he has represented the interests of working people in Western Australia for some decades."

The conviction does not disqualify Mr Bullock from running as a candidate or sitting as a senator from July 1 if he is elected.

A spokesman for Mr Bullock told AAP that the candidate regretted the incident.

"Mr Bullock does not intend to re-litigate this incident in the press now. It is an incident he regrets, but it is incorrect to say that it was unprovoked."