Iran coach Carlos Queiroz bit his tongue about Asian Cup referees on Wednesday under the watchful eye of tournament organisers following his outburst earlier this week.

Asked whether he had any concerns about the refereeing for Thursday's game with Qatar, Queiroz confined himself to some sarcastic comments.

On Sunday, the former Real Madrid and Portugal boss launched into a tirade against the officiating of Australia's Ben Williams in the 2-0 win over Bahrain.

"I don't know if we're entitled to give opinions about refs," he said, turning to the press conference moderator for confirmation. "No? All right so I didn't know that. Better not to comment."

"It's clear even if you talk politely, with respect, education, calm, cool, you're not entitled to talk about the referees," Queiroz added.

"After 32 years of my work in football I was never told I cannot give an opinion about the game. Maybe it's only because of the sponsors," he said, gesturing to the screen of brand names behind him.

Queiroz, nicknamed "Rottweiler" by Alex Ferguson during his times at Manchester United, did not hold back last week when he accused Williams of inconsistency over Bahrain's "dangerous" play.

It was one of a series of negative comments about Asian Cup referees with Japan's Keisuke Honda, Oman coach Paul Le Guen, and South Korea boss Uli Stielike also finding fault with the officials.

An Asian Football Confederation (AFC) official said coaches had been encouraged not to talk about referees during press conferences at the Asian Cup.

Iran could book their spot in the quarter-finals with a win against Qatar on Thursday but Queiroz said he wouldn't follow Australia coach Ange Postecoglou by rotating his players.

"My group is quite different from Australia's. In our group we have four candidates with the possibility to go to the second round, so we cannot take chances," he said.

"This will be the opportunity also to establish and keep the core of the team because we've not been playing so much.

"Most of the players played for the first time together in the game against Bahrain so I need to take advantage of that situation. But there will be a couple of tactical adjustments."

Queiroz added that he has the luxury of a fully fit squad to choose from, with Andranik Teymourian declared healthy despite missing training on Wednesday.

"They (Qatar) lost the first game against UAE and they're going to try their absolute best tomorrow to achieve the result because tomorrow's going to be the final chance," said the former Bolton Wanderers midfielder.

"If they want to qualify for the second round, they need to come up with the best performance tomorrow."