After two decades of talks at the World Trade Organization towards banning subsidies that contribute to over-fishing, the lead negotiator said Tuesday that a deal could be within reach.

"It's time to sprint for the finish line," Colombian ambassador Santiago Wills, who is chair of the fisheries subsidies negotiations, told reporters from the WTO headquarters in Geneva.

It is widely agreed that action is needed against over-fishing, which is stripping the seas of a hugely important resource that millions of people depend on for their livelihoods.

After missing the last deadline to reach an agreement in December 2020, negotiations have accelerated in recent months.

New WTO chief Ngozi Okonjo-Iweala, who took the reins of the global trade body in March, has made clinching the long-awaited fisheries deal one of her top priorities, and has called for a breakthrough by July.

Reaching any kind of an agreement at the WTO can be a struggle, since all decisions require a consensus among all member states.

"I know it will not be easy for 164 members to reach consensus, but it is doable," Wills insisted.

He said he had presented a new draft text to delegations, proposing "compromise language for areas where differences have persisted".

A third of commercial fish stocks were fished at biologically unsustainable levels in 2017
A third of commercial fish stocks were fished at biologically unsustainable levels in 2017 AFP / Arun SANKAR

This, he said, was a "crucial step" toward producing a clean text to present during a meeting of trade ministers on July 15.

Before that, on May 20 and 21, he said, "short, confessional-style meetings" would be held with each delegation to gain more insight into what they find the toughest to accept in the text.

"With just two months to go, I hope this sincere and honest attempt at balancing ambition and necessary flexibility will help members agree on landing zones that will make a substantial contribution to the health of our oceans," the lead negotiator said.

One of the main stumbling blocks over the years has been a UN demand that developing countries and the poorest nations receive special treatment.

The demand from some countries to be exempt from any subsidy constraints has been difficult for everyone to accept, especially since the WTO system allows members to self-identify as developing countries.

Many of the major fishing nations are considered developing countries, including China, which has one of the world's biggest fishing fleets.

Wills acknowledged Tuesday that the issue of so-called "special and differential treatment" had "been the toughest area to find convergence".

The draft text proposes to tackle this by allowing all developing countries to request an "initial time-bound exemption" to the subsidy restrictions.

After that first period lapses, countries "with a limited share of global fish catch and a limited total amount of fisheries subsidies, could seek an extension through a committee process," he explained.

Global fisheries subsidies stood at $35.4 billion in 2018, with $22 billion of that going towards building up fishing fleets, according to Ussif Rashid Sumaila of the University of British Columbia in a study regularly cited by diplomats.

Meanwhile the UN's Food and Agriculture Organization has an increasingly alarming outlook on over-fishing, finding that a third of commercial fish stocks were fished at biologically unsustainable levels in 2017.