Fluttering shearwaters are found in inshore waters around the top half of New Zealand.

At least five 'absolutely protected' native birds have been shot dead near a nature sanctuary, the Department of Conservation believes.

A man saw the fluttering shearwaters floating in the water near Little Barrier Island, about 80km north of Auckland, over Auckland Anniversary weekend.

The Auckland man, who also photographed the birds, said they appeared to have bullet holes in them.

Yuin Khai Foong, DOC's Auckland Inner Islands biodiversity senior ranger, said fluttering shearwaters have a conservation status of 'relict', meaning they have a small but stable population.

They are absolutely protected by the Wildlife Act and anyone harassing or harming them would be liable for prosecution.

If found guilty, offenders could face a jail term of up to two years or a fine of up to $100,000.

"It is very disappointing that some people don't value our native species enough or respect the legal protection they are afforded to treat them accordingly," Foong said.

"With the fine weather over the holiday weekend our rangers noted a high level of boat usage so I'm hoping someone will come forward with information that helps us to identify those responsible.

"Information gathered by the public can help in investigations, especially details which help identify those responsible. Taking clear photos of the incident at the time and quickly writing down notes of what was observed can prove to be critical in investigations."

Anyone with information can phone 0800 DOC HOT (0800 362 462).