Emergency services battled a two-acre fire on Crown land off Sandy Creek Road near Great Western from about 8pm.

Stawell Sergeant Simon Grant said the fire was suspicious.

He said police were also investigating a small fire reported just before 1am.

The five-square-metre fire was lit just outside Stawell, along train tracks near Harvey Lane.

"It was lit in a place where no-one could see it, other than the train driver who reported it," Sgt Grant said.

"It is extremely dangerous behaviour."

He urged anybody with information about either fire to call either Crime Stoppers on 1800 333 000 or Stawell Police Station on 5358 8222.