Westwood, whose opening 65 had given him a two-shot overnight lead, failed to make the early progress he was looking for after starting with eight straight pars.
But a birdie at 18, his ninth hole of the day, got him moving and three more birdies, including two to close with, saw him post a halfway total of 11-under-par 133 at the US$750,000 Asian Tour event.
At that stage he held a dominant five-shot lead over Kieran Pratt of Australia, who posted the best morning round of the morning wave, a seven-under 65.
However, Singapore's Zaw Moe whittled away Westwood's lead in the afternoon and cut it to three shots by taking his own score to eight-under thanks to an opening nine 32.
Westwood admitted patience was the key on a tough day.
"I thought it was quite tricky out there. There wasn't much wind but the flags were placed in tough positions," he said.
"If you got close, you would still have a lot of break on the putt. You want to be leading tournaments and I obviously got the hang of playing on this golf course. More importantly, I was patient and I didn't force things to happen."
Westwood said he struggled with the humidity but was delighted to finish the second round as play was suspended due to lightning shortly after he submitted his scorecard.
"Yesterday [Thursday] was quite windy and overcast. It was very hot and humid early on and I suffered with that a little bit. It is just one of those things where it can be so hot that you can't replenish the fluids. That's Asia for you. I'm going to have to fluid up this afternoon."
Pratt, playing in his second year on the Asian Tour, three-putted for bogey on his opening hole but made a superb comeback with 10 birdies against two bogeys for a total of six-under 138.
The Australian, who shot an opening 73, said: "I was frustrated yesterday. I felt like I was sort of playing okay but didn't putt very well. I never had confidence on the greens and I did a bit of work with my coach last night and sort of ironed out a few things and holed some putts.
"I've been in this position before. It is only two rounds in so I need to keep going through the weekend. Obviously, Lee (Westwood) is a world class player and he is not going to back up but we are going to go out there and chase him," said the 23-year-old.