Chatham Rock Phosphate will raise more money from investors through a share purchase plan.
The plan will offer existing shareholders the chance to subscribe for up to 15,000 new shares at 33 cents each.
That's a 17.5% discount to the market price at the close of trading on Friday.
Capital raised will be used to refine its mining system design so it can start detailed designs early in 2013, to work on its mining licence and marine consent, and for further possible research work at sea.
The money will also go towards work programmes for the Namibian exploration licences it applied for earlier this year.
The company says it remains on track to go into production by the start of 2015.