The exclusion zone around the stricken cargo ship Rena has been reduced to 3.7km around the Astrolabe reef.
The ship ran aground on the reef off Tauranga October 2011, causing hundreds of tonnes of oil and containers to spill into the sea.
The exclusion zone previously encompassed 5.55km around the wreck.
Maritime New Zealand also says boat operators should stay at least 200 metres away from any debris from the Rena and from salvage vessels working in the area.
