The Global Compact for Safe, Orderly and Regular Migration was finalized at the UN in July after 18 months of talks and is due to be formally adopted with the bang of a gavel at the start of the two-day conference in Marrakesh.

The US government disavowed the negotiations late last year, and since then Australia, Austria, the Czech Republic, Dominican Republic, Hungary, Latvia, Poland and Slovakia have pulled out of the process, AFP reported.

The US on Friday took a fresh swipe at the pact, labelling it “an effort by the United Nations to advance global governance at the expense of the sovereign right of states”.

But a host of other nations led by German Chancellor Angela Merkel are in Morocco to endorse the deal and the UN remains upbeat that it can help the world better cope with the hot-button issue.

On the eve of the conference, UN special representative for migration Louise Arbor hit back at the pact’s critics, insisting the document is not legally binding.

“It is surprising that there has been so much misinformation about what the compact is and what the text actually says,” she told reporters in Marrakesh.

“It creates no right to migrate. It places no imposition on states,” she said, adding that 159 member countries are due to attend the conference, including “around 100” represented by heads of state, heads of government or ministers.

But rows over the accord have erupted in several European Union nations, hobbling Belgium’s coalition government and pushing Slovakia’s foreign minister to tender his resignation.

From the United States to Europe and beyond, right-wing leaders have taken increasingly draconian measures to shut out migrants in recent years.

US President Donald Trump has pledged to build a wall on the US-Mexico border and has focused his recent ire on a migrant caravan from Central America, while a populist coalition government in Italy has clamped down on boats rescuing migrants at sea.

Beyond Merkel, among European nations the leaders of Spain, Greece, Denmark and Portugal are set to attend, although French President Emmanuel Macron is sending his secretary of state for foreign affairs as he deals with the “yellow vest” protests at home.

Belgium’s liberal premier Charles Michel won the support of parliament to head to Morocco and back the accord, but he was left leading a minority government on Sunday after the Flemish nationalist party said it will quit his coalition over the pact.

Belgium is among a group of seven nations described by Arbor as still “engaged in further internal deliberations” over the accord, with Bulgaria, Estonia, Italy, Israel, Slovenia and Switzerland also falling into this category.

Billed as the first international document on managing migration, the global pact lays out 23 objectives to open up legal migration and discourage illegal border crossings, as the number of people on the move globally has surged to more than 250 million.

But while welcoming the UN’s attempts to manage migration, activists argue that the pact does not go far enough to secure migrants’ rights.

“Unfortunately, the non-binding nature of the Global Compact on Migration makes its implementation solely based on the goodwill of states supporting it,” Amnesty International’s senior advocate for the Americas, Perseo Quiroz, said in comments emailed to AFP.

After the Marrakesh conference, the UN General Assembly is set to adopt a resolution formally endorsing the deal on December 19.