Egyptian authorities grounded a Libyan Airlines flight on Wednesday after an attendant found a suspected bomb in a toilet on the aircraft, airport officials told AFP.

Tripoli-bound flight 203 was due to leave Cairo International Airport when a member of the cabin crew found "a metal object" in one of the plane's toilets shortly before take-off.

"The captain immediately informed security authorities at the airport. Security officials and bomb experts boarded the plane and found a tear gas canister," the official said.

"After a thorough search, nothing else was found on the plane and officials are now questioning the 75 passengers on board," he said.

The plane will remain in Cairo until an investigation is carried out.