A former Australian professional golfer has accused American amateur Stewart Hagestad of cheating his way through the 2017 US Masters.

Golfer turned broadcaster, Mark Allen, questioned whether Hagestad should have received the honour as best-placed amateur in the Masters event, suggesting the American flouted the rules about controlling a long putter with his upper body.

Allen told Melbourne sports radio station SEN that Hagestad’s approach was “absolutely disgraceful” as it gave him an unfair advantage.

He said the American had anchored his putts by resting a long putter against his chest during the stroke, a practice that was made illegal last year.

“If he wasn’t cheating with that long putter, I’m not here. That was unbelievable,” Allen told SEN.

“The rules say your arm is allowed to accidentally brush your shirt (when putting). Well, he ‘accidentally’ brushed his shirt with that arm and that left hand using a broom action every single time I saw him putt.

“Bernhard Langer is still doing it and Ian Woosnam (too).

“What an absolute joke.”

Was Stewart Hagestad anchoring? Watch The Masters:

Allen said Australian amateur Curtis Luck was a more deserving recipient of the best-placed amateur honour.

“You almost had the situation where he (Luck) wins the US Amateur, wins the Asian Amateur Championship and he should’ve been the leading amateur here at Augusta, except for the guy cheating with the long putter,” he said.

Allen was not the only one to question Hagestad’s use of the long putter.

Viewers were also highly critical of his approach.

“How is Stewart Hagestad’s putting stroke not illegal?” one fan wrote.

“My goodness, Hagestad’s putting grip looks incredibly close to anchoring. Very close,” another tweeted.

Former world No.1 and one of Australia’s most notable long putter users Adam Scott was forced to change his game last year, which saw his ranking drop to 36th in the world.

The move was initially feared to be career threatening after a very poor performance using the conventional putter at the Florida Swing in 2015.

But Scott took a proactive step towards the end of 2015 to begin using a conventional-length putter with a new grip style and has since clawed his way back up to rank 11th.

Despite continuing struggles at short-range, Scott’s perseverance with the new approach began paying off, with a lead on the final nine of his second event of the year at Riviera in 2016.

If I were #AdamScott I'd have fire coming out of my eyes watching #hagestad putting that way… @usga @PGAcom @TheMasters

— Kevin Runion (@KPRunion) April 9, 2017

Two-time US PGA Tour winner Brett Ogle told the Australian Golf Digest that most have been pleasantly surprised by how well Scott has been playing since the rule change.

“What the long putter did was give Adam confidence on the greens again,” Ogle said.

“Now he’s adopted a similar putting technique with the short putter.”