Five players, including Anna Nordqvist who tied for the round of the day with a 65, are tied for fourth at 4-under.
Webb won the Australian Women's Open two weeks ago and Nordqvist took the Honda LPGA Thailand title Sunday.
Also in the 4-under group is Caroline Hedwall, who was 4-over for the final three holes Friday. She had a 7 at the par-5 18th after bogeys at 16 and 17.
Webb, who had a bogey-free 66 Thursday, opened her second round with a bogey but turned in four birdies and made the turn at 3-under. She birdied No. 12 but slipped with bogeys at 13 and 15. A birdie at the par-3 17th moved her two strokes ahead of the field.