Salvage work on the bow section of the shipwrecked Rena will start within the next day or so, the new US salvors say.

But details of how the salvage will proceed are not yet being released.

Salvage work would start "tomorrow", Resolve spokeswoman Martha Lord told NZ Newswire from the company's head office in Florida on Friday (NZT).

She couldn't release more details because of a confidentiality agreement with the ship's owners, she said.

Resolve has been appointed to remove the wreck.

The Rena ran aground on the Astrolabe reef off Tauranga in October last year, spilling oil and cargo into the sea, in what became New Zealand's worst maritime environmental disaster.

Salvage company Svitzer has completed its task of removing the oil and containers from the wreck.