A cargo ship lost 83 containers overboard during heavy seas off Australia, and items including nappies and sanitary pads are washing up on beaches.

There are fears the ill-fated containers will pose a hazard for shipping and whales.

The YM Efficiency, operated by Taiwan shipping company Yang Ming Marine Transport Corporation, was sailing from Taiwan to Sydney when it encountered 5-metre swells in the Tasman Sea, about 30 kilometres off Australia's east coast late on Thursday.

"They're 40-foot containers, they sit about a foot or two off the water ... even in the best of conditions they're difficult to spot, but at night and in a swell, almost impossible," Roads and Maritime Services executive director Angus Mitchell told a television channel on Saturday.

The Liberian-registered vessel rolled heavily in the foul weather causing the 83 containers to slide off, while another 30 were damaged, the New South Wales Roads and Maritime Service said on Saturday.