Widespread Energy is meeting with brokers in Canada to try to raise money to fund the mining of phosphate on the seabed of the Chatham Rise.
The energy exploration company was granted a two-year prospecting permit in February 2010 to explore an area 450 km east of Christchurch.
Phosphate is used to make fertiliser and the resource is potentially worth $6.7 billion.
The company says it has raised about $1.5 million over the last 15 months from its own shareholders.
Managing director Chris Castle says it is now trying to attract Canadian shareholders to raise about $34 million.
Chris Castle says the money will be spent on trial mining and further exploration of the resource, with mining possibly beginning in 2013.
He says the mining will be carried out by European dredging companies.
Mr Castle says developing the resource would also have environmental benefits, as the local reserve appears to have much lower levels of toxic chemical cadmium than imported phosphate.