A five-day test of unmanned aerial vehicles - or drones - to deter illegal fisherman from Palau's waters has come to an end.

The tiny Pacific nation says it hopes to use drone patrols to deter illegal fishermen from using its waters in what officials believe is a world-first use of the technology.

Palau has only one patrol boat to cover it's economic zone which is roughly the size of France.

This makes it a prime target for illegal trawlers.

President Tommy Remengesau said the drones showed potential to "greatly increase the efficiency of our surveillance capability and, most importantly, significantly decrease the overall cost of the joint surveillance effort."

Other Pacific countries have expressed interest in using similar measures for patrolling.

The idea of using the drones emerged after Australian mining magnate Andrew Forrest visited Palau in January.

Mr Forrest asked his Minderoo philanthropic foundation to examine the illegal fishing issue.

Greg Parker from the Minderoo Foundation said Mr Forrest was not going to stand back and watch Palau be bullied by illegal fisherman.

"[He] absolutely loves the pristine environment of Palau and also loves the people there," Mr Parker said.

Aside from patrolling, the drones can also be used for search and rescue purposes and to map and survey marine wildlife.

Palau is already regarded as a leader in marine conservation after creating the world's first shark sanctuary in 2009.