A friend of murdered Saudi journalist Jamal Khashoggi is suing an Israeli software company he believes helped the kingdom intercept messages sent to him from the dissident criticising Mohammed bin Salman.

Omar Abdulaziz, a Saudi national who now lives in exile in Canada, filed a lawsuit on Sunday against NSO Group alleging its spyware helped the Saudi government gain access to his smartphone.

The spyware allows its customers to secretly listen to calls and read messages on a targeted phone.

The lawsuit, filed in Tel Aviv, accuses NSO Group of breaking international laws by selling its software to oppressive regimes.

"The hacking of my phone played a major role in what happened to Jamal, I am really sorry to say," Mr Abdulaziz said. "The guilt is killing me."