Sylvester Stallone. Picture: AP

Sylvester Stallone will take on a Mexican cartel in 'Rambo 5'.

The 71-year-old actor - who first played the Vietnam veteran in 1982 - is said to be working on a script for the new movie, while his 'Expendables' collaborator Avi Lerner is on board to produce.

According to Screen International, the movie - which is expected to start shooting in September.

The former soldier has been working at a ranch, but when the daughter of one of his friends is kidnapped, he crosses the US/Mexico border and finds himself up against one of the country's most violent organisations.

Stallone was initially expected to direct the movie as well as star, but that's not now believed to be the case.

John Rambo was the lead character in the 1972 novel 'First Blood', written by David Morrell. The book was adapted into a film of the same name in 1982.

The franchise then spawned sequels 'Rambo: First Blood Part II' in 1985 and 'Rambo III' in 1988. 

Whilst the former was a box office hit, the latter of the two flopped when it hit screens, and the character subsequently lay dormant until Stallone revived him for a 2008 movie simply entitled 'Rambo'. 

Stallone is currently working on another franchise, 'Creed II', the follow-up to Rocky spin-off 'Creed', and earlier this year was filming 'Expendables 4', despite previous speculation he'd quit the series.

In April 2017 Nu Image/Millennium chief Lerner hinted Stallone had quit the franchise due to creative "disagreements" with him, but admitted there was still a chance he could be involved in the fourth film.

He said: "We've got disagreements with Sly, but we've had them for over a year and a half. Right now, each one has opinion. We agreed on 95 per cent of things, but there are certain things in production we don't agree on. 

"I don't think it's over, but what write whatever you want. In my opinion, it's not dead."