The Washington Post columnist, who was a critic of Saudi Crown Prince Mohammed bin Salman, has been missing for more than two weeks after he entered the Gulf kingdom’s consulate.
Turkish officials said police searching the consulate found evidence the journalist was killed there, while brutal accounts surfaced of his alleged slaying as he tried to pick up paperwork to get married.
The Labour leader on Wednesday called for an international investigation into the “abominable” treatment of Mr Khashoggi.
“The issues that have come to light of the death in Istanbul of a Saudi national who was visiting the embassy call into question the close relationship with Saudi Arabia of so many Western countries,” he told US broadcaster CNN.
“Our immediate call is for the suspension of all arms supplies to Saudi Arabia.”
Saudi’s behaviour in Yemen, where it has been accused of war crimes during the civil war, must also be challenged, Mr Corbyn added.
His comments came after Foreign Secretary Jeremy Hunt and his G7 counterparts said they are “very troubled” by the writer’s disappearance and called for those responsible to be held accountable.
On Wednesday, Turkish investigators searched the home of the Saudi consul general in Istanbul, which is a short distance from the consulate where Mr Khashoggi disappeared as his fiancee waited outside on October 2.
An account in Turkey’s pro-government Yeni Safak newspaper alleged Saudi officials cut off his fingers and decapitated him.
US secretary of state Mike Pompeo visited Turkey for talks following a meeting with the Saudi king and the crown prince.
Trump has suggested that “rogue killers” could have been involved in the case but such a move without sanction from the Saudi regime is believed by many to be highly unlikely.