WITNESSES are being sought to identify a person who deliberately lit a fire in Victoria's north on Tuesday.

A fire that broke out in Timmering, near Rochester, is suspected to be linked to 18 previous fires in the area, the Herald Sun reports.

Rochester CFA quickly contained the fire in Webb Road, which broke out about 4.30pm just east of Thornton Road, near a road side drain.

Arson and Explosives Squad detectives say it is too early to link this incident to other fires.

Det Sen Sgt Chris Murray said although similar, they cannot rule anything in or out.

"As is always the case with arson related crimes, we appeal for members of the public to have the courage to speak up and call Crime Stoppers with information'', he said.

"If you know or have seen anything, we ask you call to assist us to stop these serious crimes before they get out of hand.''

A second fire which also occurred yesterday in a hay shed about 8pm in Burgoine Road, Rochester, is also under investigation.

The cause of the fire is yet to be determined but detectives are treating it as suspicious.

• Anyone with information about either fire can call Crime Stoppers on 1800 333 000.