The blaze took hold on private land bordering Linton State Forest about 1.30pm.

The fire caused concern on a day where temperatures reached the mid-30C. It continued to burn into the afternoon as the mercury climbed to nearly 33C.

About 20 volunteers controlled the blaze within 45 minutes, but remained on scene well into last night as the ground continued to smoulder. Fire investigators and Moorabool Police Criminal Investigations Unit detectives are

investigating the cause.

Fire Authority incident controller Reinhard Pohl said the cause of the fire appeared suspicious.

"We believe it needs to be investigated, the cause is not immediately obvious and there is nothing there that could have sparked it," he said.

Mr Pohl said the fire began in a tree in a valley before moving north uphill through grass and surrounding trees.

He said while moderate fuel loads on the forest floor and a lack of wind yesterday helped firefighters to contain the blaze quickly, it gained intensity as it spread.

It crossed Happy Valley Crossing Rd as CFA volunteers arrived on scene, but did not threaten any nearby houses or livestock.

"Until we put control lines in, it was never a huge threat but until we arrived it had the potential to cause damage," he said.

"It didn't spread quickly but it goes to show the community that even though there was a moderate fuel load and no wind, it's already causing us problems."

Mr Pohl said the blaze served as a timely warning to landowners that the fire risk was already high, just two weeks into the fire season.

"We really have to start being careful, people need to start cleaning up around their properties and to have their (fire) plans in place and to make sure to be careful with fire in the bush," he said.

Six CFA units from Linton, Scarsdale, Smythesdale, Mannibadar and Cape Clear attended yesterday's fire.