Nick Kyrgios has paid the price for his "insulting" comment to Stan Wawrinka at the Rogers Cup after being fined by the ATP.

The temperamental Kyrgios once again hit the headlines for the wrong reasons on Wednesday when he was heard telling Wawrinka that fellow Australian Thanasi Kokkinakis had slept with his girlfriend. 

The 20-year-old said: "Kokkinakis banged your girlfriend. Sorry to tell you that, mate," during his Rogers Cup second-round clash with Wawrinka in Montreal.

In an on-court interview after the Swiss had retired during the third set due to a back injury, Kyrgios said: "I thought he was getting a bit lippy at me so... it's just in the moment sort of stuff, but yeah, I don't really know, I just said it."

Australian Open champion Wawrinka called on the ATP to take action over a "disrespectful" comment which he "wouldn't say to my worst enemy".

And the governing body have now hit Kyrgios in the pocket for his on-court sledge.

An ATP spokesman said: "The ATP has announced that‎ Nick Kyrgios has been fined for an insulting remark made to Stanislas Wawrinka during his second-round match against Wawrinka at the Rogers Cup in Canada.

"Further details of the fine will be made after that player has been notified."

Kyrgios later issued an apology on Facebook.

He said: "I would like to take this opportunity to apologise for the comments I made during the match last night vs Stan Wawrinka.

"My comments were made in the heat of the moment and were unacceptable on many levels. In addition to the private apology I've made, I would like to make a public apology as well. I take full responsibility for my actions and regret what happened."