The commission - responsible for managing the vast ocean waters - meets in Papua New Guinea this week.
The Pew Charitable Trust has said due to the high volume of fishing vessels, trans-shipment (transfer of catch between fishing and carrier vessels) and port activities in the region, the Commission had been unable to increase its observer coverage.
The Trust said the commission needed to strengthen oversight of fishing vessels at sea, and in port, and modernise management for long-term sustainability.
Jamie Gibbon, of the Trusts' international fishing team, wrote in an article for Pew that illegal, unreported and unregulated fishing was a major threat to the sustainability and profitability of the world's fisheries.
He said sound fisheries control also required clear rules regarding how much fish could be caught and with what gear.
Mr Gibbon said that would help fishing levels become sustainable.
To achieve that, the commission should strengthen port controls, increase observer coverage and improve monitoring of trans-shipment.
The commission also needed to advance harvest strategies and protect the sharks, mantas and mobula rays.
Meanwhile, Fisheries Minister Semi Koroilavesau will lead the Fiji delegation at the meeting and said he would discuss crew policies to ensure Fijian nationals were protected on local and foreign fishing vessels.
He said the supply of tuna from several of its neighbours would also be high on the agenda for Fiji at the meeting.
"I think PNG, Solomons and Vanuatu would be ready to discuss the details of it. We have been working with the Ministry of Foreign Affairs for the last year in trying to achieve this."
Mr Koroilavesau said Fiji would also push for a quota system given the number of foreign fleets on the high seas.
That, he said, would protect smaller and developing Pacific states.
Mr Koroilavesau urged Pacific governments to improve control over their fisheries to protect their value.
The Western and Central Pacific Fisheries Commission meeting starts on Thursday in Port Moresby.