The Swedish government urged citizens to avoid travel to Japan following the devastating earthquake and tsunami that hit the country.

"Due to the natural disaster in Japan the Foreign Ministry advises against non-essential travel to the stricken areas (prefectures) Aomori, Iwate, Miyagi, Fukushima and Ibaraki", said a travel advisory issued by the department.

Norwegian and Danish officials went further, also cautioning against travel in the provinces of Akita, Yamagata and Tochigi, with the Danish foreign ministry citing "the problems around the nuclear plant Fukushima," where it is feared two reactors may have suffered a meltdown.

"Prime Minister Fredrik Reinfeldt expressed condolences on Friday to the Japanese people and expressed his sympathy at this difficult time", the statement added.

The Swedish Radiation Safety Authority is following developments in Japan day and night, Swedish Radio said. It has decided to keep the phone lines open on Sunday if worried Swedes want to speak to an expert about what is happening.

Japan battled a feared meltdown of two reactors at a quake-hit nuclear plant Sunday, as the full horror of the disaster emerged on the ravaged northeast coast where more than 10,000 were feared dead.

Japan's government said Sunday it expects the economic impact of Friday's huge 8.9-magnitude quake, and the devastating tsunami that followed, to be "considerable".

The National Police Agency's official death toll as of early Sunday was 688, with 642 missing and 1,570 injured.

No reports of injured Swedish nationals or causalties have reached the Swedish Embassy in Tokyo.

"The Embassy is following the developments closely and are getting in touch with all registered Swedes presumed to be in the most seriously affected areas. Swedish nationals residing in Japan are advised to monitor news reports and to follow advice from local authors", a statement said on the Embassy's website. 

The areas to be avoided "are all close to the nuclear plant," the Danish ministry said, also cautioning that "Japan is still being hit by recurring, powerful aftershocks."

The Norwegian foreign ministry meanwhile warned against travel to the same area, and said "travellers to other parts of Japan should be aware of delays and changes in public transportation and follow the current advice from local Japanese authorities."