Mark McGhee has accused Scotland striker Tony Watt of not being fit enough and relying too much on natural ability.

The Charlton goalscorer, who is on loan at Blackburn until the end of the season, is in the national squad for Thursday's friendly away to Czech Republic.

McGhee has admitted he would like to send Watt to a boot camp in America in a bid to improve his fitness because he believes it will make him a better player.

Speaking to the newspapers, the assistant manager said he could become a crucial part of the country's 2018 World Cup qualifying campaign if he takes drastic action to get into shape.

"Tony is one of these boys who is not fit enough," he said. "He doesn't train hard enough. I know if you could get him to work hard in training, he would be a better player.

"He relies so much on natural ability and he lets himself down because he can’t go the distance.

"First and foremost, I would really be looking to get him fit. Tony is not as fit as he could be, but also mentally he is one of these boys who coasts a wee bit.

"He believes in his own natural ability, that he can come into a game at any point and contribute when the ball comes his way. Don’t get me wrong, I'm not talking about a player here that’s three stone overweight.

"The boy looks in great shape in that respect. But it’s just getting him to work that bit harder in training and in games."

Watt was handed his first call-up to the senior Scotland squad for the away win in Croatia in 2013, but has not featured for the national side since.

The 22-year old struggled after leaving Celtic in 2014, failing to make an impact at Belgian side Standard Liege.

He has since moved to England in an attempt to kick-start his career, but was loaned to Cardiff before joining Blackburn in January.

McGhee believes the striker has the ability to be a success but says he his lack of commitment frustrates him.

"I remember saying ‘I would love to work with you every day’, and I would," he added. "Tony is the sort of player I would love to get a hold of and really smack around.

"If you were working with him, I would think that you could improve him. He’s at a club now at Blackburn where maybe he will be able to do that.

"I remember speaking to Neil Lennon about Tony. There was a point where I thought, ‘Don’t let him near a football’ — set him certain targets and standards before he gets another kick of the ball.

"Send him to one of these places in America that get you fit, a boot camp. If he can improve his fitness by X factor, he’s going to be a better player."

The assistant manager wants Watt to prove his worth before the qualifying campaign gets under way in September and says that should start this week in training.

"He’s got tremendous ability and I hope we can throw down gauntlets to him," he added. "I hope we can throw down challenges and incentives to Tony about coming here again and being part of this campaign.

"We can tell him what he has to do back at his club in order to persuade Gordon Strachan that should be the case. It might be incremental, but I think we can do that."