Australian golfers Greg Chalmers and Robert Allenby are four strokes off the lead and tied for sixth midway through the second round of the US PGA Tour event at Torrey Pines in California.

The pair have moved to eight under par for the tournament but are still four adrift of Korean Sang-Moon Bae who leads at 12 under.

Rod Pampling and Nick O’Hern are the next best Australians in a tie for 24th at five under par.