Chatham Rock Phosphate says it's on track to raise $1 million in new capital from its shareholder share purchase plan.
The company has an exploration licence covering more than 4500 square kilometres of the seabed east of Christchurch which it believes contains significant deposits of rock phosphate and other potentially valuable minerals.
It wants to extract the rock phosphate to provide an alternative source of fertiliser to the 1 million tonnes imported each year, mostly from Morocco.
Chatham Rock Phosphate chief executive Chris Castle says he's thrilled by the extra investment which reflects three years of strong progress by the company.
He says the number of shareholders has risen from 300 to 430 since last September.