A plan to produce power for 250,000 homes from tidal turbines in Kaipara Harbour, north of Auckland, has been put on hold.

Anthony Hopkins, who steered Crest Energy through a three-year resource consent application process for the project, said electricity market uncertainty, including the outcome of the partial floating of state-owned generators, was to blame.

He has sold almost all his Crest shares to Todd Energy and said his appetite for investing in renewables had gone.

"Lots of people put a huge amount of effort into the project and you don't get that back. That's a shame but you can't cry over spilt milk."

The Kaipara project, which would have seen 200 turbines up to 20m high being driven by the harbour's 9km/h current, is just one of half a dozen marine energy schemes that have stalled or been canned.

According to John Huckerby, who headed marine energy body Awatea for seven years, the sector has made significant advances but ultimately failed to deliver power to the national grid.

"That was because of a lack of continuity of Government funding."

Crest was one of several companies to get Government grants - most of which were not taken up - to help install marine generators. Hopkins said the money would have been more helpful in the project planning phase.

"The reality is if you want projects to advance they need seed funding to get them to the point of commercialisation where they can attract proper funds."

He wouldn't disclose how much he had sunk into the project but said he was happy with what Todd paid for his shares.