A FIRE that started on the Western Freeway median strip on Friday night is being treated as suspicious.
Nerrina residents were forced to evacuate shortly after midnight after embers from the five-hectare fire landed on their properties.
Ballarat Police Crime Investigation Unit Detective Sergeant Steve Howard said the fire was being treated as suspicious.
Investigations found the fire had been started in two separate places on the median strip a fair distance apart.
More than 20 CFA tankers were called to the scrub fire at 11.50pm.
The situation worsened when the fire jumped to the southern side of the freeway into bushland at the rear of Brown Hill.
One Nerrina resident told The Courier that "quite a few" people left their houses due to the bushfire and that embers were flying into backyards in Waranga Street and Nerrina Road.
The fire tore through five hectares of bush and scrub before it was brought under control in two hours.
Ballarat City CFA Senior Station Officer Mark Owen said the CFA recieved "dozens" of emergency calls from concerned residents and motorists.
Ballarat Police enforced a road block just after midnight between Victoria-Daylesford Road and the Midland Highway. VicRoads assisted in traffic management shortly afterwards.
Any witnesses are urged to contact Detective Sergeant Steve Howard at the Ballarat Police Station on 5336 6000, or for anonymous reports contact Crimestoppers on 1800 333 000.
At the same time crews were called to the Nerrina fire, a small grass fire broke out on a vacant block at the intersection of Vickers and Grant Street in Sebastopol.
Two tankers brought the fire under control in a short time.
Crews were also called to Humffray Street South in Golden Point where a fire had started next to the Yarrowee Creek.
Earlier in the night crews were called to Bonshaw Drive in Sebastopol at 8.16pm to reports of a bin fire.
The temperature in Ballarat was 33 degrees at the time.