The environmental group Guardians of the Sounds is hoping a flotilla of 100 or more boats on September 29 will ram home the anti-salmon farm expansion message to the Environmental Protection Authority and the Government.

Chairman Peter Beech, who also organised a large flotilla in protest at the speed of the Cook Strait ferry Kaitiaki in 2006, said he couldn't estimate how many boats would take part, but feeling was running high.

"Last time we didn't have the boating clubs involved, and we had more than 100 boats. This time the clubs are all in behind it."

A board of inquiry set up by the authority has been hearing an application by Nelson-based New Zealand King Salmon to add nine more salmon farms to its existing five in the Sounds.

The hearing, which began in Blenheim on August 27, is expected to continue for several more weeks.

Mr Beech said the protest would begin with a land-based hikoi from Waikawa Marae to Waikawa Marina, about a 20-minute walk, then the flotilla would depart for Tory Channel.

The boats would assemble in a large bay on the Picton side of the Te Pangu salmon farm in Tory Channel at around 11.30am.

They would then circle that farm before crossing the channel to the Clay Point salmon farm on the other side and then head to the nearby site of a proposed farm.

He had already had discussions with the police, harbourmaster and the Coastguard.

It was likely that the police launch Lady Elizabeth would travel across from Wellington to act as the command vessel, with the Coastguard and harbourmaster providing safety patrol boats.

It was about a 45-minute trip from Waikawa to Tory Channel in a runabout, and about 1 hours in a launch.

Yachts, and possibly kayaks, would also likely be involved, with yachties asked to use their motors only so that the flotilla could be more orderly.

The point of the flotilla was to make it plain that the protesters didn't want the NZKS application, if successful, to pave the way for others, Mr Beech said.

"We're really concerned that once this gate is opened, it will create a gold rush for companies wanting to obtain the water space of our Sounds.

"We regard it as public common, the public domain, and we guard it very jealously."

He said although the salmon farm hearing was well under way, the short time allowed for submissions had been a tremendous frustration to many of the group's 500 or so members, Sounds property owners and users.

"An awful lot of people would have liked to have put submissions in, but didn't.

"This is a way for us to demonstrate to the Government and this hearing, just the strength of opposition that there is to what's going on."

The flotilla would not go ahead if the weather was unsuitable.

A decision on that would be made close to the time.

The group might also ask that any Cook Strait ferries due to use Tory Channel while the protest was going on consider using the northern entrance to Queen Charlotte Sound instead.

- © Fairfax NZ News