Powerful typhoon Chaba barreled toward Japan's southernmost Okinawa island chain on Monday, cancelling more than 300 flights, as authorities issued their highest warning for the storm.

The violent storm was moving northwest near Okinawa, packing gusts of up to 306 kilometres (190 miles) per hour, Japan's weather agency said.

The agency also issued an emergency warning, its highest alert, suggesting the typhoon could be the strongest in decades and cause serious damage.

With the storm closing in, authorities in Okinawa's capital Naha issued an evacuation advisory for its 320,000 residents, according to public broadcaster NHK, but there were no immediate reports of damage or injuries.

The storm is set to hit Japan's main island of Honshu later this week and then move through the Japanese archipelago, the agency reported.

More than 300 flights have been cancelled due to the typhoon as Naha airport, the region's gateway, remained closed Monday afternoon, NHK said.

Classes at primary and secondary schools in Okinawa were also cancelled Monday, according to media reports.

Big storms regularly strike Japan, with 22 people killed when Typhoon Lionrock pounded the country last month, while another person was killed when Typhoon Malakas ripped across the country in September.

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