The eight-time European No 1 said the use of green reading books and players meticulously lining up lines on the ball before hitting a putt was “really annoying me”.
Montgomerie took to Twitter to air his views after the pace of play at Austin Country Club had been criticised on air by Sky Sports Golf commentator Ewen Murray.
The second of the two last-four matches in the $10.5 million event involving American duo Scottie Scheffler and Matt Kuchar took four hours and eight minutes.
Even allowing for a troublesome wind, Montgomerie expressed his disgust about how long players were taking in two separate social media posts.
“100% agree,” he said on hearing fellow Scot Murray’s comments. “Pace of play is ridiculous. No one in front of them. Green reading books, lining up the lines on the ball. Really annoying me. And matchplay is the fastest form of golf. Something has to be done #slowplay.”
He later added in response to a TV image of both players and their caddies consulting their yardage books, “All four have their yardage books out.
“They’ve played the hole with practice nine times this week. Stood there for two minutes doing nothing! Slow play needs to be penalised.”
Montgomerie, one of the quickest players in the game, has regularly called for action to be taken against the game’s slow coaches.
In 2019, he backed four-time major winner Brooks Koepka for speaking out about the problem after playing with JB Holmes in the final round of The Open at Royal Portrush.
"We all should play quicker, and I think it really is hurting the game," said Montgomerie. "We are told that your playing partner doesn't affect you, or shouldn't affect you because it's your own ball and you only control your own ball.
“But, at the same time it threw him [Koepka]. He did well to recover and finish fourth but it threw him. It's interesting it even throws the best players.
"It's killing our game and the penalties are not severe enough, the deterrent should be a lot more severe than it is."