SAO PAULO, Nov 30 (Reuters) - Brazilian petrochemical producer Braskem is facing a new 1 billion real ($203 million) lawsuit over damages that its salt mines have caused sinking ground in the city of Maceio and forced evacuations, the company said on Thursday.

The lawsuit, which state and federal prosecutors filed against the company and the city, seeks an expanded risk area related to ground subsidence and requiring Braskem to compensate more families.

The announcement comes after Maceio's civil defense office warned on Wednesday that Braskem's salt mine number 18, located near a lake in the Mutange neighborhood, was at imminent risk of collapse.

The city, in the northeastern coastal state of Alagoas, said on Thursday the soil movement in the area "remains with the same intensity" recorded on the previous day, when there were 23 families still occupying properties in the region.

"Since yesterday, more than half of these properties have already been vacated," the city said.

It was not immediately clear what the city's role was according to the lawsuit.

The company's rock salt mining activities in the area, which were halted in 2019, led to soil subsidence that forced the interdiction of several neighborhoods in Maceio.

Braskem has set aside 14.4 billion reais so far to address issues related to the sinking ground in the city, authorities attributed to its decades-long salt mining activities carried in Maceio's underground.

The company has disbursed 9.2 billion reais of the total provisional funds since 2018, when the crisis deepened when cracks in streets and buildings formed in five neighborhoods.

It was not immediately clear if the amount the lawsuit seeks is already included in the company's provisions.

This week, executives said that Braskem expects to finish relocating and compensating the city's residents affected by the sinking in early 2024.

($1 = 4.9182 reais) (Reporting by Alberto Alerigi Jr.; Editing by Josie Kao)