Senior, an Australian who was tied with fellow countryman Steve Collins after the first round, had eight birdies and one bogey on the 6,852-yard, par-72 Hyatt Regency resort course.
'I was really happy with the way I got going, and I thought I could birdie every hole,' said Senior, who is at 15-under 129 overall.
Rod Pampling is second at 134 after a 69 on Friday. Peter O'Malley, Nick O'Hern and Craig Parry are tied for third at 135, six strokes back of Senior. Collins had a 73 to drop into a tie for seventh with Adam Scott (69) and Stephen Allan (67).
Jean Van de Velde of France, trying to come back from a serious knee injury, had his second straight 69 that left him nine strokes back of Senior and tied for 10th. Americans Ryan Palmer and Stewart Cink were in a group of seven with Van de Velde, Cink with a 67 and Palmer with a 69.
Greg Norman, using tennis player Lleyton Hewitt as his caddie, had an inconsistent day with two double bogeys, two bogeys and four birdies for a 2-over 74. He's tied for 31st and 12 shots back of Senior.
American Rich Beem, the 2002 PGA champion, shot a 69 and is at 2-under 142, 13 strokes back.
The cut was made at even-par 144, leaving American Matt Weibring (145) and former PGA champion Wayne Grady of Australia (151) out of weekend play.
Copyright 2003 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.