As salvage workers continue to dismantle the stricken ship Rena, debris from the cargo it was carrying continues to wash ashore, with tiny polymer beads proving to be problematic.

This month alone, clean-up workers have picked up thousands of the beads, which have largely contributed to the 3.5 tonnes of debris collected in August.

The small, light beads were found stretched across the Coromandel coast, but clean-up efforts have also being underway on Matakana Island in the Bay of Plenty, Maritime New Zealand (MNZ) said today.

While stretches of beach in the Coromandel were now clear of beads, there were pockets where concentrations of beads were still being found.

The Rena was labelled New Zealand's worst environmental disaster when the cargo vessel struck the Astrolabe Reef, off the Tauranga coast, on October 5 last year.

About 350 tonnes of oil and dozens of containers spilt into the ocean.

Salvage workers were now working to dismantle the ship, with the last week proving "highly productive", MNZ said.

Eighty five individual pieces of steel were removed this week, bringing the total amount of steel removed to 300 tonnes, most of which has come from the Forecastle Deck area.  

Bay of Plenty Regional Council continues to oversee the Rena oil spill response. While the Tier 2 response was today downgraded, the council said it would continue to respond to reports of oil washing up as part of its day to day business.

- © Fairfax NZ News