Speaking after his Australian Open doubles exit, Hewitt says he's cut all contact with Tomic following the alleged abuse over the past 18 months.

Hewitt says he tried to help Tomic - who this week criticised his Davis Cup and Open wildcard player selection policy - but believes the 26-year-old former Australian No.1 is now a lost cause.

Hewitt said he'd received multiple threats from Tomic.

"Both (physical and verbal) - blackmail and physical," Hewitt said on Thursday night.

"The threats that I've received for me and my family that I've had had for a year and half now, I don't think anyone would reach out to a person who speaks like that.

"For me, it was the abuse I copped from him at the end. I drew a line in the sand and I haven't spoken to him since.

"He won't play Davis Cup while I have anything to do with it."

Hewitt said he didn't feel threatened by Tomic's abuse but was frustrated after trying to help the world No.88 and one-time No.17.

Describing him as a "clown", he said he was disappointed by Tomic's most recent comments.

"For me, the biggest frustration is that I really went out of my way to help him," Hewitt said.

"I spent a lot of time with him at a lot of tournaments and tried to get a coaching structure and physical team around him to give him the best opportunity but at the end of the day he kept making the wrong mistakes.

"Deep down, Bernie knows what I've done for him ... for Bernie to come out and have a go but more to get all of his facts wrong, that's probably the most disappointing thing."

Australia's qualifying tie next month in Adelaide is against Bosnia and Herzegovina and Nick Kyrgios is also unlikely to play a role due to his sliding ranking and his attitude.

With players like Australian No.1 Alex de Minaur, John Millman and exciting teen Alexei Popyrin on the rise, Hewitt said he didn't need players who wouldn't give their all for their country.

Hewitt said Kyrgios wasn't lost to the Davis Cup cause but needed to match the cultural standards set by the team and he hadn't spoken to him about attitude and his controversial comments on social media.

"Nick still has a lot to learn," he said.

"The biggest thing 'Rochey' (Cup coach Tony Roche) I have is to set cultural standards and I feel Nick isn't meeting those.

"The things we feel like we have to push - all we ask is to commit to the sport, go out there and give 100 per cent every time you step on the court."

Australian Associated Press