Vanuatu police have briefly detained the chairman of the Maritime Authority, Christopher Emele, in a corruption probe.
They seized computers from his company, Tuna Fishing, from the Authority offices and the Department of Fisheries.
Our correspondent says at the centre of the investigation is the allegation that a letter was recently signed by the fisheries minister, Steven Kalsakau, to allow a Taiwanese ship to fish in Vanuatu waters.
There are also concern of a possible conflict of interest over Mr Emele's company allowing Taiwanese vessels to fish while he is charge of monitoring foreign vessels in Vanuatu waters.
The opposition leader, Willie Jimmy, has called on Mr Emele to resign.