The United States said Wednesday more work was needed on reforming the WTO's dispute settlement system, denying accusations by India that it is bringing the trade body to a standstill.

US Trade Representative Katherine Tai spoke on the sidelines of the World Trade Organization's 13th ministerial meeting (MC13) in Abu Dhabi, where trade ministers discussed an embattled system of settling trade disputes.

Washington brought the system to a grinding halt in 2019 after blocking for years the appointment of new judges to the WTO's appeals court, the organization's highest dispute settlement authority.

Dispute settlement reform is a "hard issue" but the dynamic in the negotiating room at MC13 is "constructive, its positive, its sober," Tai told reporters.

But "there is more work to do," she added, following a working session on the issue.

During the last WTO ministerial in 2022, member states reached a commitment to having a fully and well-functioning dispute settlement system in place by 2024.

The overall outcome of MC13 is only expected to reiterate this commitment, despite demands by some member states, including India, for stronger progress at the Abu Dhabi talks.

Tai said "convergence is happening" on various areas of dispute settlement reform.

But "there is another set of issues that are going to be harder and that are going to take longer to address, including what to do with the appeals mechanism and how to have a mechanism for review that doesn't repeat the problems of the appellate body that came before it," she said.

Washington has accused the appellate body of over-interpreting WTO rules, with Tai on Wednesday saying the now-defunct body was formerly more powerful than member states.

It was "extremely activist, extremely powerful, more powerful than even the members, where members could secure new rules through litigation and not have to rely on the very hard work of negotiating with each other," she said.

Washington's push for reform has angered India, which accused the United States on Wednesday of bringing the WTO to a "standstill".

India threatened to hold off on any new deals before an agreement is reached on the appellate body.

"It's important that the first issue we should settle is that there should be an appellate body and some countries are not allowing that to happen," India's commerce minister Piyush Goyal told AFP.

"The entire working of WTO currently has come to a little bit of a standstill".

Responding to his remarks, Tai said: "there is nothing standing still in this ministerial conference."

"If the appellate body were still operating as it had in the past," member states would not have reached the outcomes they did at MC12, she said.