A reputed New York mobster has been found not guilty for his alleged role in an infamous $6m heist dramatised in the hit film Goodfellas.

A jury reached the verdict on Thursday at the federal racketeering trial of 80-year-old Vincent Asaro.

The aging gangster was accused of helping plan the 1978 Lufthansa robbery at New York's Kennedy Airport - the largest cash theft in US history.

Prosecutors used wiretap recordings and testimony from Mafia turncoats in their bid to take down Asaro.

Among those to testify was Asaro's cousin, Gaspare Valenti.

He told jurors that Asaro and Lucchese crime family associate James "Jimmy The Gent" Burke - portrayed by Robert De Niro in Martin Scorsese's 1990 blockbuster - killed a suspected informant with a dog chain in 1969.

Valenti also testified Asaro drafted him for the Lufthansa heist, telling him, "Burke has a big score at the airport coming up, and you're invited to go".

Prosecutors said Asaro gave Burke his blessing for the robbery, which took place on what was considered Bonanno turf.

They also claimed he collected at least $500,000 from the heist, but still complained about not getting what he thought was his fair share.

In one wiretap recording played in court, Asaro was heard saying, "We never got our right money, what we were supposed to get. ... Jimmy kept everything."

Prosecutors said Asaro gambled away much of the money he received from the score.

Asaro's defence lawyers said prosecutors relying on shoddy testimony from ageing gangsters with incentives to lie.

It was reported that Valenti turned on his cousin because he was cheated out of his cut from the airport heist.