England's Tommy Fleetwood was the surprise halfway leader at the Thailand Golf Championship, edging ahead with a composed display in tricky conditions.

Fleetwood followed up his opening round 71 with a three-under-par 69 to finish the second round perched on top of the leaderboard at four-under-par.

That left Fleetwood one shot clear of compatriot Lee Westwood (71) and Australia's Marcus Fraser (72) at three-under.

Thailand's Tirawat Kaewsiribandit, who only earned his spot in the field after coming through a qualifying tournament, carded a 72 to grab a share of fourth place with American Jonathan Moore (71).

Germany's two-time major winner Martin Kaymer shot a 72 to be in a three-way tie for sixth at one-under, while reigning Masters champion Bubba Watson climbed 37 places up the leaderboard with a 70 and Spaniard Sergio Garcia lost ground when he signed for a 75.

Fleetwood was one of just 12 players who broke par in the swirling winds at the Amata Spring Country Club, on the outskirts of Bangkok.

"I played really well and had only about three or four bad shots. That's what you need to do on a course with windy conditions like this," said Fleetwood.

"Compared to Thursday where I had to scrap out a result and shoot a one-under, which was unbelievable."

Westwood, who won the tournament in 2011, was well poised for another run at the title after a solid round.

"It was tricky out there. The wind was blowing a bit stronger than yesterday," he said. "All in all it was a good round and three-under will put me in a good position for the weekend."

Fraser was also pleased with himself after only recently returning following an eight-month lay-off caused by a wrist injury.

The Australian made a double-bogey on his third hole, but birdied the fourth and 11th holes to finish the day all square.

"It's reassuring to know you're doing the right things and preparing properly for a tournament after having so long out of the game," he said.

Garcia, last year's champion, said he played better than his score suggested, but paid a heavy price for two mistakes.

"I just couldn't get anything going. Hit a lot of good putts but nothing went in," he said. "The two shots I missed I made two doubles, so you know, that's the way it is."

Meanwhile, expectant father Adam Scott shot a three-under-par round of 69 to close within two shots of the lead at the halfway stage of the Australian PGA Championship.

Scott, who revealed before the start of play that his wife is pregnant with their first child, followed up his opening-round 68 to head into today's third round at seven-under-par.

That left the world No.3 alone in third place, just two strokes behind his fellow-Australians Wade Ormsby and Scott Strange, who finished at nine-under.

American Boo Weekley, who led overnight after the first round was suspended because of thunderstorms, fired an even-par 72 to remain at six-under, but dropped back to fourth place on a heavily-congested leaderboard.

Six players, including Nick Cullen, who beat Scott by a shot to win last month's Australian Masters, ended the day at five-under, while a total of 44 players were under par.

Conditions on day two were perfect at the Royal Pines Resort Queensland, near where Scott was raised, and the defending champion made four birdies but gave back a shot with a bogey at the par-four 13th hole.

"I really want to finish this off with a win and hang on to trophy this year and go into next year feeling a little bit chuffed with myself," Scott said.

"It was really solid golf from tee to green today, just a bit frustrated not to take advantage of a few more of the holes."

Ormsby and Strange had contrasting rounds. After making a bogey on his opening hole, Ormsby made an eagle at his third, the par-five 12th, then reeled off four birdies in a row from the 14th.

He made another birdie on the third hole, his 12th, then made a late bogey for a round of 67.

Strange produced the round of the day, a flawless six-under-par 66. He made a solid start, with two birdies on his front nine, before picking up four more on the run home, including one on his last hole to join Ormsby in the lead.

"I think we got the right side of the draw with the storms and that rolling in yesterday and this morning with the rain," said Strange.

"So I took advantage of it and played nice today."