Japan conducted a national earthquake drill on Saturday after the government unveiled a worst case disaster scenario that warned a monster jolt in the Pacific Ocean could kill over 320,000 people.

The annual drill also came shortly after a tsunami warning was temporarily issued in Japan late Friday following a 7.6 quake that struck off the Philippine coast -- reminiscent of last year's disaster in northeastern Japan.

Police suspended traffic at some 120 points in central Tokyo to spare lanes for emergency and military vehicles while passengers were guided to safe zones from train stations in a simulation of a post-quake scenario.

Throughout Japan, about 387,000 people were scheduled to take part in the drills.

Prime Minister Yoshihiko Noda, wearing working clothes, held a mock emergency news conference at the prime minister's office and called on people to act orderly for evacuation.

Disaster Prevention Day is an annual exercise to train for a potentially deadly magnitude-7.3 quake scenario in Tokyo and is held to commemorate the anniversary of the 1923 Great Kanto Earthquake, which killed more than 100,000.

On Wednesday, Japan's government said many of the estimated 323,000 victims could be killed in a scenario that sees a powerful undersea quake of about 9.0 magnitude unleashing waves of 34-metres (112 feet).

On March 11 last year, a 9.0 magnitude quake struck seismically-active Japan, triggering massive tsunami that left some 19,000 dead or missing and sent reactors at the Fukushima nuclear plant into meltdown.