WASHINGTON: A US judge has ordered Georgia's governor and the mayor of Atlanta to sit for mediation in their legal spat over the mandatory wearing of face masks to combat COVID-19.

Republican governor Brian Kemp sued officials in the US state's largest city Thursday, seeking to block a mandate that would require Atlanta residents to wear face masks in public.

Kemp claims mayor Keisha Lance Bottoms does not have the authority to require stricter public health measures than the state, which has encouraged mask-wearing but not required it.

In an order issued Thursday, Georgia's Fulton Superior Court Judge Jane Barwick ordered Kemp and Bottoms to attend a mediation before Tuesday 28 July where they should "make a good faith effort to resolve the issues involved in this case."

The mediation will be overseen by another judge, the order added.

Georgia has recorded more than 130,000 COVID-19 cases and is one of the worst-hit states in the US.

National public health officials have for months urged face coverings as a means to limit the outbreak, with studies highlighting that even cloth masks can reduce oral particle dispersion between 50 and 100 percent.

Alabama, California, Texas and Colorado have instituted state-wide mask mandates to try to curb surging infection rates.

But mask requirements have led to friction in stores around the country, spawning numerous viral videos of irate customers clashing with retail employees.

And US President Donald Trump has mostly declined to wear a mask in public, only donning one for the first time last week.