Senior Constable Chris Taylor from Ballan Police said the men were travelling east when their car ignited about 3.45pm, less than one kilometre east of the Ballan-Daylesford Rd.

Sen Const Taylor said the men had been conducting survey work in a paddock on Ballan-Daylesford Rd, and it appeared that dry grass became caught under their ute and ignited on part of the exhaust system as they travelled along the highway.

Sen Const Taylor said both men escaped the vehicle and Ballan CFA volunteers extinguished the blaze. The ute was extensively damaged.

One lane of the highway was temporarily closed as the scene was cleared.