WASHINGTON, Nov 6 (AFP) - A US federal appeals court on Saturday (Nov 6) halted a vaccine mandate by President Joe Biden's administration that is intended to push millions of workers at businesses with more than 100 employees into getting COVID-19 shots.

The New Orleans-based US Court of Appeals for the Fifth Circuit said that because petitioners "give cause to believe there are grave statutory and constitutional issues with the Mandate, the Mandate is hereby STAYED pending further action by this court".

The traditionally conservative court ordered the government to reply to the motion for a permanent injunction by 5pm local time on Monday.

Petitioners include five strongly Republican US states - Texas, Louisiana, South Carolina, Utah and Mississippi - as well as several private companies and religious groups.

If upheld, the suspension would represent a stunning setback to one of Biden's most far-reaching and high-impact efforts to secure the widespread immunisation of American workers ahead of a winter when a resurgence of COVID-19 is expected.

There was no immediate reaction from the Biden administration.