The European Union, China and 18 other countries and territories on Thursday launched a temporary system for appealing trade dispute rulings after the US-provoked collapse of the WTO appeals body.
The participants in the arrangement formally notified the World Trade Organization Thursday that the temporary appeals mechanism had entered into force.
The "interim appeal arrangement for WTO disputes becomes effective," the European Commission said in a statement.
The multi-party interim appeal arbitration arrangement (MPIA) is aimed to "reduce the uncertainties created by the situation of the WTO appeals body," the Swiss government explained in a separate statement.
The move comes after the WTO appeals panel, sometimes dubbed the supreme court of world trade, halted its operations in December after years of US opposition.
Washington, which accuses the court of serious overreach, has blocked the appointment of new judges, leaving it without the quorum of three needed to hear cases due to mandatory retirements.
Ahead of the December 11 shutdown, Canada and the EU struck a bilateral deal last July to set up an interim panel to hear appeals in disputes that might arise between Brussels and Ottawa.
Since then, a number of other countries have joined.
In addition to the EU, Canada and China, the participating countries and territories are Australia, Brazil, Chile, Colombia, Costa Rica, Guatemala, Hong Kong, Iceland, Mexico, New Zealand, Norway, Pakistan, Singapore, Switzerland, Ukraine and Uruguay.
The countries argue that the new system is designed to preserve the principle enshrined in international trade law that governments have the right to appeal in any dispute.
It is based on Article 25, a rarely-used provision of the WTO Dispute Settlement Understanding.
According to Thursday's notification, any appeals filed under the temporary system will be heard by three appeal arbitrators selected from a pool of 10 international trade law experts, who are "unaffiliated with any government".
The MPIA arbitrators will have 90 days to reach a verdict following the filing of the appeals notice, with the possibility to request a 90-day extension.
The participants, who have all committed to adhere to the ruling, have stressed that the temporary system will cease to exist once WTO's true appeals body begins functioning again.
The US has had wide-ranging concerns about the WTO appellate branch that predate President Donald Trump.
The administration of former president Barack Obama began a policy of blocking the appointment of appeals judges over concerns that their rulings violated American interests.
But Trump's trade team both extended that policy and escalated the fight, arguing in particular that the US Constitution does not permit a foreign court to supersede an American one.
US concerns regarding the WTO appeals court include allegations of judicial overreach, delays in rendering decisions and bloated judges' salaries.