A typhoon which struck Japan in late September has produced insured losses of up to $US600 million ($620 million), modelling firms say.

Typhoon Roke made landfall as a category two storm near the city of Hamamatsu in Shizuoka prefecture on September 21, some 250km southwest of Tokyo.

AIR Worldwide says it was primarily a wind event, and has put the bill at $US150 million ($155 million) to $US600 million in insured losses.

Fellow cat modeller Eqecat puts the loss estimate from Roke slightly higher at $US300 million ($306 million) to $US600 million ($612 million).

It says tropical storm-force winds and rainfall affected the Fukushima area and site of the nuclear power plants that were damaged in the March earthquake, with the possibility that rain run-off may spread some of the leaked radioactive material in the area and exacerbate the clean-up exercise.

Meanwhile, AIR Worldwide has revised its loss estimates for Hurricane Irene, which hit the US east coast last month.

It says that due to updated information about insurance penetration, it has revised its insured loss estimate for the damage Irene caused to the Bahamas down from $US300 million-$US700 million ($306 million-$715 million) to $US200 million-$US400 million ($204 million-$409 million).

AIR Worldwide’s loss estimates from Irene for other countries in the Caribbean remain unchanged, as does its loss estimates for the US, which is still $US3 billion-$US6 billion ($3.1 billion-$6.1 billion).