Defending champion and world No. 1 Karrie Webb is four shots off the pace after posting back-to-back rounds of 2-under 70.
Munt, who shot a bogey-free 65 to lead by one after the opening round, picked up where she left off with four birdies over the first six holes Friday to get to 11-under par. She went 3-over the rest of the way, however, bogeying the seventh, 11th, 15th and 16th against one birdie at the 12th.
'I suppose you could say I got a bit wobbly on the back nine, but I knew it was going to be a long, hard day out there and I played well,' said the 35-year-old Munt, a two-time winner on the Evian Ladies European Tour last year. 'I'm still pretty pleased with how it all went.'
Munt, a member of the LPGA Tour in 1996, tied for seventh at last week's Australian Ladies Masters.
Dibnah, the winner of 13 European Tour titles, matched three birdies with three bogeys Friday for an even-par 72. She is searching for her first victory since 1994.
Monnet posted five bogeys, including two over the last three holes, on her way to her second straight round of 3-under 69. The 22-year-old Parisian placed third on the Order of Merit last season after notching nine top-10 finishes.
Sophie Gustafson (69), Jane Crafter (71) and Elisabeth Esterl (71) are three shots back at minus five.
Webb, who captured an unprecedented fourth consecutive Australian Ladies Masters title last week, was less than satisfied with her three-birdie, one-bogey effort in round two.
'I played a bit scratchy. I did have a few chances but I didn't putt very well today,' said Webb, who was six shots down heading into the weekend last week at Royal Pines. 'I think I missed a good four or five putts from 10 feet. It was not a round that had a lot of momentum, but until the last hole I didn't make any mistakes either.'
England's Laura Davies experienced an up-and-down 69 on Friday that consisted of seven birdies and four bogeys. She is currently alone in eighth place at 3-under 141.