A New Zealand company denied the right to mine phosphate from the ocean floor says the detention of a shipment of phosphate in South Africa shows it was right all along.
Chatham Rock Phosphate lost an application before the Environmental Protection Authority (EPA) to mine phosphate from the seabed off the east coast of the South Island.
Since then, 55,000 tonnes of phosphate have been seized in South Africa, en route for New Zealand, and political activists are promising more such actions.
They said the phosphate was mined in the Western Sahara, which was illegally occupied by neighbouring Morocco, making its export unlawful.
The shipment is one eighth of New Zealand's total annual needs.
Chatham Rock Phosphate chief executive Chris Castle said this development underlined the strategic value of New Zealand's own deposits.
His company sought to extract up to 1.5 million tonnes a year of phosphate from Chatham Rise, 450km off the East Coast of New Zealand, at a depth of 400m.
The company plans to re-submit its application to the EPA for reconsideration.
In the meantime it is closely watching a similar application by Trans Tasman Resources (TTR) which wants to mine ironsands from the sea floor off the coast of South Taranaki.
TTR was also turned down first time around but has come back with a second attempt to win approval.
Mr Castle added New Zealand phosphate would be low in cadmium, a poisonous metal often found in phosphate deposits.