Specialist sniffer dogs have been used to check predator-free islands off Northland's coast after a boat broke a mooring and drifted onto rocks sparking a conservation scare.
A six and a half metre boat, formerly used as a commercial crayfishing vessel, drifted from Flat Island near Great Barrier Island andaided by winds and sea currents beached in Boulder Bay on Whatupuke Island - in the Hen and Chicken Islands.
Department of Conservation ranger Marie Jordan said there were concerns there may have been rats on the boat that might have survived the journey and disembarked on the island, which is home to a large number of protected plants.
The islands are a no go zone unless a permit has been obtained from the department.
DoC officials went to the island last Thursday to help the owner, who had tracked down his boat.
Ms Jordan said as a precaution two dogs trained to sniff out rodents were used to check three islands in the chain. Traps were also checked and they showed no sign of unwanted animals.
Ranger Neil Forrester said he helped pick up parts of the boat that were strewn across the small bay. The bottom of the boat had been ripped out and the owner reported all the electrical gear and radio had been stripped off.
That raised more concerns people had landed on the island without permission.
