Dozens of containers lost off a cargo ship near Port Stephens have been spotted on the sea floor, with more rubbish expected to wash up on the Australian coastline in coming days.

The Australian Maritime Safety Authority (AMSA) on Tuesday revealed as many as 50 containers had been identified, either broken apart or intact.

“The search has been successful so far but hampered by poor weather with the search suspended on occasions,” a spokesperson said.

“Search operations are expected to be completed later this week.”

YM Efficiency was making its way from Taiwan to Sydney when it was hit by heavy swells.

It lost 81 containers about 30 kilometres off Port Stephens in the Hunter region.

A hydrographic survey vessel engaged by the cargo ship insurers began the search for lost containers on June 22.

“The search to date has identified a number of targets, which may amount to as many as 50 containers, either broken apart or intact, on the sea floor within the search area,” AMSA said.

Just two of 81 containers have washed up. Photo: AAP

The containers are yet to be verified, and are expected to be confirmed about a week after the survey is completed.

The risk containers pose maritime operators will then be assessed.

Only two containers have washed ashore, according to NSW Maritime.

About 942 square metres of waste – including yoga mats, nappies, car parts, packaged foods, clocks and sanitary items – had been picked up by late last month.

UNSW Canberra researchers tracking the debris say more is expected to wash up on the Australian coast in coming days.

“According to our simulations, at this moment some debris may be still near Port Stephens, while other debris is moving away from the coast following currents, in particular following the eddies of the East Australian Current,” researcher Isabel Jalón Rojas said on Tuesday.

“This offshore debris may be brought back by the same eddy in the coming days.”

The debris and containers will move differently depending on what they’re carrying and how damaged they are.

The current model created by UNSW researchers tracks the debris in surface waters. The team is working on a model to track the debris route beneath the ocean’s surface.

CSIRO physical oceanographer David Griffin last month told The New Daily he would not be surprised if debris was washing up in Queensland or Tasmania six months later.

The Australian Transport Safety Bureau is investigating the incident.

Debris sightings should be reported to the Roads and Maritime Service at 13 12 36.