Club chairman Hootie Johnson has again been left to defend Augusta National as he came under intense questioning over controversial changes to the course. And he was unflinching in the face of criticism from the world's best golfers and the media.

Tweaked and stretched to an imposing 7,445 yards, the layout that will test golfers this week is the second longest in major championship history.

Six of the holes have been lengthened with new tees, and some of the fairways have been narrowed with extra bunkering, trees and rough.

Torrential rains over the last four years have diluted the effect of the alterations, but with sunshine forecast for the week, Augusta National has finally started to bare its teeth and many of the top players are not happy.

Johnson, however, made no apologies and would not rule out more changes.

"We are comfortable with what we are doing with the golf course for the Masters tournament," he said.

"I said, we are comfortable," he fired back when pressed on the criticism from top players. "They are entitled to their opinion."

Some of the most outspoken critics have been Augusta's greatest champions, including Tiger Woods and Jack Nicklaus and Arnold Palmer, who between them own 14 green jackets.

Some players have complained that playing Augusta is no longer as much fun as it once was, to which Johnson responded championship courses were not supposed to be fun.

In an attempt to keep pace with the advances in technology, Augusta's guardians insist the face-lift is part of an effort to maintain the course's integrity and ensure it will be played the way it was designed.

"I didn't know a tough golf course was supposed to be a lot of fun," Johnson said. "I don't know that hitting a six-iron on one would be any more fun than it was 20 years ago.

"There's been a lot of talk about 11. The hole was intended to be played with, according to Bobby Jones, a three-iron or stronger club.

"I think it was in the 98 tournament I was out there, and Phil Mickelson hit a big driver and had a pitching wedge to the green.

"You can say it's a bomber's course, but if he's going to really bomb it, if he's going to swing from the heels, if he doesn't execute perfectly he's going to pay the price."