Israel has confirmed that the victim of a plane crash in Greece was a witness in a trial involving former prime minister Benjamin Netanyahu, as Greek officials launched an inquiry.

Senior Greek air safety official Ioannis Kondylis said a fisherman who witnessed the incident near Samos island yesterday, claimed he had heard two explosions, though the cause of the crash is not yet known.

The Israeli foreign ministry identified the victims of the Cessna C182 single-engine plane crash as Haim and Esther Giron, an Israeli couple, both aged 69 and from Tel Aviv.

Haim Giron, the former deputy director at the communications ministry, was scheduled to testify at a trial involving Mr Netanyahu, the Israeli prosecutor's office told AFP.

Among several charges, Mr Netanyahu is accused of giving regulatory favours to media moguls in exchange for favourable coverage.

Mr Giron had been expected to testify on allegations that the former PM negotiated with a telecommunications firm to secure positive coverage in exchange for policies benefitting the company.

The Greek civil aviation agency said the four-seater plane had taken off from Haifa on a private flight, and disappeared from radar shortly before its scheduled landing at Samos island airport.

Mr Kondylis, head of the state air accident investigation and aviation safety board, said a team of specialists would fly to Samos tomorrow to inspect the wreckage.

"A fisherman said... there was a large explosion, followed by a smaller one," he said.

"The wreckage will show if that's the case," Mr Kondylis said, adding that the wreckage was around 33 metres underwater.

The wreckage location is 2km south of the airport, he said, adding that he was "hopeful" there would be more clarity on the causes of the crash over the next two weeks.