The first fire broke out at Glenrowan at 4.30pm, the second at Laceby at 4.43pm and the third at Winton minutes later.

CFA district 23 operations manager Paul Horton said the short time and distance between the grass fires, pointed to them being deliberate.

Fire investigators were on the scene last night.

“A number of items that were found were taken away for investigation,” Mr Horton said.

“They’re of enormous interest to us.”

Mr Horton would not disclose what the items were but they would be passed on to police.

He said up to eight brigades controlled the blazes quickly, helped by an aircraft.

Mr Horton said the aircraft had been in the area to check for lightening strikes earlier in the day and was on hand for the grass fires.

“We were able to deploy that and get some really good intelligence for our brigades on the ground,” he said.

Warnings were given to residents at Winton, Glenrowan and Laceby due to the smoke that had drifted across the highway.

Mr Horton said anyone seeing what could be an out-of-control fire should phone triple-0 and residents planning burn-offs should ring 1800 668 511 to register with the CFA.