The Australian government on Friday directly urged its citizens to leave Tokyo and vicinity, in an upgraded travel advisory that alluded to concerns about radiation exposure for the first time.

''If you are an Australian citizen currently in Tokyo...and your presence is not essential then you should leave,'' Foreign Minister Kevin Rudd said in an interview with Nine Network.

He said the advice also applies to areas north of Tokyo on the main island of Honshu that were affected by last week's earthquake and tsunami.

The latest travel advisory issued by the Department of Foreign Affairs and Trade cites ''disruptions to essential services, infrastructure damage, strong aftershocks and continuing uncertainty about the status of the Fukushima Nuclear Power Plant.''

It says Australians in Tokyo and affected areas ''should, unless their presence in Japan is essential, make arrangements to leave -– either to Southern Japan or elsewhere.''

The previous travel advisory, issued Wednesday, had merely urged Australians in Tokyo and vincinty to ''consider departure'' in view of the breakdown of essential services, and it made no mention of concerns over explosions at the nuclear power plant in Fukushima Prefecture.

Rudd said Australian consular officials are stationed at Tokyo airports ''assisting Australians onto flights and making other practical arrangements as is necessary.''

He said that while there is still good availability on commercial flights out of Japan, his government is also engaged in contingency planning in case the situaton changes.

There are still no reports of Australian casualties in Japan.

Rudd said 14 Australians are still unaccounted for in areas affected by last week's natural disaster, down from an initial list of 143.

''We're going from morgue to hospital to emergency shelter to get this list down and we're then seeking to transport Australians who we find from there back to Tokyo,'' he said.

==Kyodo