Slow play has emerged as the biggest problem on the US PGA Tour and the game needs to speed up even at the amateur level, according to 2012 US Masters champion Bubba Watson.

The rule-makers of golf have outlawed the anchoring of putters from 2016 but Watson felt slow play was a more important issue that merited greater attention.

"We are worried about putters and golf balls and all these things, but I think we should be more concerned about slow play and speeding the game up," said the American, "not just for pros but for amateur golfers, as well.

"Nobody wants to play a game that takes 5 1/2 hours to play. We want everybody to be able to play and go a lot faster," the lefthander told organisers of the Asian Tour's Thailand Golf Championship, which he will play in later this year.

Chinese teenager Guan Tianlang was slapped with a one-stroke penalty at Augusta this year with Japan's Hideki Matsuyama, 21, also penalised at the British Open.

"Nobody wants to see a young kid, a young player get that penalty. That penalty is not a fun penalty to get ... happened to be Asian players, but I think the youngsters can learn from that," Watson said.

"Slow play is a problem on the PGA Tour, and I think that's our biggest concern," added the American, who will return to Thailand in December hoping to improve on his second place finish last year.

The 34-year-old golfer, however, had no real concerns about his own game despite a title drought since winning the Masters last year.

"I am happy with my game. Obviously you want to produce better scores. You want to win," said the golfer, who has had three top 10 finishes this season. "I haven't won yet, but I'm playing well. I feel like I'm playing good."

Certainly not as good as Tiger Woods, who is back at the top of the world rankings with five victories this year and, according to Watson, looking good for his 15th major even in a constantly improving field.

"The world is getting better at golf, and I think every major he plays in now, there are better and better players," said Watson.

"Yes, he can easily win a major. He's the number one in the world. He's the greatest ever. So, yes, he can win another major.

"I don't know if he ever will, but yes, he can easily do it. He's good enough to win any tournament."