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.

YM Efficiency lost 83 containers overboard off the central coast. Credit:shipspotting.com

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.