Poachers' history of switching flags

New Zealand officials have widened their net in the search for the owners of three fishing vessels caught poaching toothfish in the Southern Ocean.

Foreign Minister Murray McCully said he had now spoken with Equatorial Guinea's Foreign Minister Agapito Mba Mokuy, who had confirmed that the Songhua, Kunlun and Yongding were falsely claiming to be flagged to the African country.

Interpol records showed the vessels had changed flag several times, previously claiming to be flagged to Indonesia, Tanzania, Mongolia, Cambodia, Sierra Leone and other countries.

Two of the ships appeared to be owned by Panama-based Stanley Management Inc, which Mr McCully said was likely to be a shell company.

The Ministry of Foreign Affairs and Trade was now working with Panamanian officials to investigate this link.

New Zealand was also in communication with Spanish authorities, because two of the vessels were previously owned by a notorious Spanish syndicate called Vidal Armadores.

"Everything we have seen points to Vidal Armadores continuing to control and manage this illegal activity in the Southern Ocean," Mr McCully said.

The company was fined by the Spanish Government in 2008 after a New Zealand investigation uncovered its illegal activity, which was carried out using one of the same ships intercepted by the navy this week.

On Wednesday, Equatorial Guinea gave New Zealand permission to board the fishing vessels but attempts to get onto the ships failed and the HMNZS Wellington has now returned to port to refuel.

Crew on board the Wellington captured evidence of the three ships - which were not permitted to fish in the region - hauling in Antarctic toothfish using illegal methods.

An Interpol purple notice said the Songhua's gillnets were "laden with toothfish", which was known by poachers as "white gold" because of the price it fetched in high-end markets.