PANAMA CITY (AFP) - The North Korean freighter Chong Chon Gang exited the Panama Canal on its way home on Saturday, more than nine months after it was seized with an undeclared cargo of Cuban arms.

"The Chong Chon Gang passed through the Panama Canal early this morning bound for Pyongyang with 10,200 tons of sugar," the lawyer for its crew, Mr Julio Berrios said.

Panama Canal administrator Jorge Quijano confirmed the ship had transited the canal without incident.

Its passage largely puts an end to a saga that began July 10, 2013 when the ship was boarded on suspicion it was carrying drugs from Cuba.

No drugs were found, but authorities uncovered tons of Cuban weapons, including MiG-1 fighters, missile launchers and military vehicles hidden under sacks of sugar.

The ship's 35 crew members were arrested and the ship and cargo seized for potential violations of a UN weapons embargo and as a threat to the canal's security.

After paying a one million dollar fine, the ship was allowed to leave on Feb 15 with 32 crew members, minus its cargo and three senior crew members charged with arms trafficking.

The Chong Chon Gang sailed back to Cuba to pick up a replacement cargo of sugar and returned through the canal.

Its passage was briefly delayed by some technical problems with its engines and electrical system.