But the former Wimbledon champion admits Kyrgios has to learn when to use his passion and fire as a weapon and when it will become destructive to his game.

Australia's No. 1 player has been put under the blow torch this week following outbursts, smashed racquets and code violations during his Australian Open matches and labelled as cocky in his post-match interviews.

He was fined $4500 for racquet abuse and audible obscenity from his round-one triumph.

But rather than curb the brash and raw approach, Cash urged Kyrgios to continue being an entertainer as he finds his feet in the professional world.

"It's him, I've got to be honest and say I've been disappointed with the higher people in Tennis Australia criticising Nick openly. I don't think that's right," Cash said.

"He's got the personality, that's why he plays that way. That's what you want, the X-factor and that brashness. You don't want to take that away.

"He may have to learn when it becomes negative and when it's not, but it's part of him. That's why he's a good player and that's why he's a good talent.

"Get rid of that and you get rid of flair out of the boy. I heard that all the time when I was a young player and so did my coach, they said, 'you've got to calm this kid down, you can't be behaving like that'.

"My coach said let him be. You want to cut the fire out of the kid [Kyrgios]? That's not right, that's what will make him a great player. I think that's what's going to make him a great player and if it gets out of control, have a quiet word."

Channel Seven commentator Jim Courier compared Kyrgios to a young version of eight-time Grand Slam winner Andre Agassi.

Agassi burst on to the international scene as a 16-year-old and established himself as one of the rockstars of the professional tour before mellowing in his later years.

Kyrgios has also been working with Davis Cup captain Pat Rafter, who has been tough on the rising star in the past to help him stay composed on the court.

After the first round at Melbourne Park this week, Rafter said: "Nick knows exactly how I feel. I think it's important for him to be a bit more level; he's still too emotional. It really shows up on the court."

Kyrgios, 19, emerged as a future star when he beat then-world No.1 Rafael Nadal at Wimbledon last year and he has captured the attention of Australia as attention on his life intensifies.

The Australian Open is his last Grand Slam tournament as a teenager and he jokes his lairy hairstyles will stop when he turns 20.

Cash rates the Canberra prodigy as a potential multiple Grand Slam winner in the coming years, if he maintains his intense approach to his game.

"You learn when your game is being constructive and destructive, that's part of it," Cash said.

"There were a couple of matches early on in my career where I lost my temper and I lost matches because of it. I learnt very quickly.

"To embarrass the kid nationally by telling him off, I think it's ridiculous. Some of the people who are criticising are legends and I understand that, you take that on board.

"But I've heard some criticism from people who were at the very least average players. For them to criticise Nick, I don't care what position they're in, it's not very productive at all."

Cash likened Kyrgios' big-hitting game to that of retired Australian champion Mark Philippoussis.

"If he keeps improving, I'd like to see him win multiple Grand Slams," Cash said.

"There's a lot of competition around, but that competition won't be around when Nick is at his peak. There's Nadal, Federer and Novak Djokovic, but in four year's time, who's there?

"A few guys, but there will come a lull and Nick's in the right position to grab some big wins with a bit of luck."