Portugal's Cristiano Ronaldo refused to comment on suggestions he deliberately got booked against Israel to ensure his availability for the World Cup qualification playoffs next month.

The Real Madrid forward was cautioned late on in the 1-1 draw for protesting to the referee, which means he will be suspended for the final group match against Luxembourg on Tuesday.

With Portugal almost certain to finish runner-up to Russia the suspension means Ronaldo will definitely be available for the playoff match, but the attacker refused to discuss the yellow card.

"I can't talk about that [booking]," Ronaldo told reporters. "FIFA is always very attentive to those situations."

"The playoff is the most important and I don't want to be out. I will be at those two matches."

Portugal are second in Group F, three points behind Russia but with a much worse goal difference than the leaders, who travel to Azerbaijan on Tuesday.