Defending Open champion Darren Clarke has described the rough at Royal Lytham and St Anne's as "brutal".
The Northern Irishman said the long, lush grass was a problem in certain areas and predicted some players would lose balls this week. Championship organisers the R&A insist, however, the course is in the best possible condition it can be.
But Clarke said: "There are a few patches out there where it's just absolutely brutal. The grass is a little bit thicker than what you normally find on a links golf course. It's really, really tough. If you start spraying the ball around this week, you might as well go home."
He added: "Obviously you start missing the fairways there you're really going to struggle so it's a big challenge. There's a really huge premium on accuracy this week. There's no chance coming out of this rough at all. There could be some lost balls in there, even with spotters and everything."
Clarke's comments followed similar remarks made by Tiger Woods, a three-time winner of the Claret Jug, who described the rough as "inescapable" after his practice round on Sunday.
Woods was quoted by various papers as saying: "Oh my God. It's just that you can't get out of it. The bottom six inches is so lush. The wispy stuff, we've always faced that at every British Open. But that bottom six inches, in some places it's almost unplayable. I've never seen the rough this high or thick and dense."
The R&A blamed unprecedented weather conditions for hampering preparations over the last few months and claim they have canvassed opinion from several professionals who are satisfied with the course.
"The feedback we have had from a large enough body of players to be satisfied that they represent the field is that it is fair and well set up," R&A communications director Malcolm Booth told Press Association Sport.
"The weather we have had, unprecedented in this country, means there has been a lot of moisture and rain which, combined with at least some summer heat, has led the rough to be very thick in places.
"[But] We are pleased with the course set-up. The fairways are suitably scaled to allow a generous landing area if you are hitting the right club off the tee. The weather will keep the fairways softer too so things aren't going to be kicking off fairways with quite the force they would have been doing at Hoylake in 2006."