Police have laid charges against the skipper of a protest boat who was arrested while disrupting an oil survey ship yesterday.

Elvis Teddy, the captain of San Pietro, was arrested for breaching the Maritime Transport Act after police boarded his boat yesterday morning amid protests against Brazilian company Petrobras's search for oil.

Mr Teddy was charged with operating a vessel in unsafe manner under section 65 of the Maritime Transport Act, a police spokesman told NZPA today.

He was released on bail last night to appear in court in Tauranga on Friday.

Police said they were still reviewing evidence and may lay further charges.

The maximum penalty for the offence is up to 12 months in prison or a fine of up to $10,000.

San Pietro, manned by local iwi, was stationed, along with three other protest boats, in front of the survey ship Orient Explorer in the Raukumara Basin, off the coast of Gisborne, police said.

After repeated warnings the three other boats moved away but the San Pietro stayed and deployed buoys and fishing lines in the path of the survey ship, causing "grave safety concerns" for the ship's master, Superintendent Bruce Dunstan said.

After further warnings police, who had been stationed on nearby navy ships, boarded the San Pietro from inflatable boats.

Mr Teddy was arrested and taken back to the navy warship HMNZS Taupo, and returned to Tauranga police station.

Mr Dunstan said the arrest followed a "blatant safety breach".

Mr Teddy's lawyer, Dayle Takitimu told Radio New Zealand he would challenge police claims the protesters acted dangerously.

San Pietro was stationary and more than 1.5 nautical miles, or 2.8km, from the Orient Explorer when it radioed the ship to advise it of its location, Ms Takitimu said.

Because the survey ship was moving, under collision regulations it had to give way to the San Pietro, she said.

Before yesterday's arrest, tribal leader Rikirangi Gage radioed the captain of the Orient Explorer and told him he was not welcome in the waters.

"We are defending tribal waters and our rights from reckless Government policies and the threat of deep sea drilling, which our hapu have not consented to and continue to oppose."

San Pietro is owned by East Coast iwi Te Whanau a Apanui and is part of the flotilla including Greenpeace and the Nuclear Free Flotilla, in its third week of opposing deep sea oil drilling.

The Maori Party is working on a bill that would force the Government to consult iwi before granting licences for offshore oil exploration.

Petrobras is operating under a five-year licence granted by the Government and the Maori Party, which has a support agreement with National, has been accused of not doing enough to back iwi.

Petrobras could not be reached for comment.