CARS travelling on a Melbourne freeway were forced to swerve to avoid Molotov cocktails thrown onto the road overnight.

Four fire bombs were thrown onto the Monash Freeway in the city's east shortly after midnight today, starting a grass fire on the side of the road.

Vehicles travelling outbound had to swerve to miss the flaming bottles.

The Metropolitan Fire Brigade was called to the scene and extinguished the roadside fire.

Police believe two of the bottles containing flammable liquid were thrown from a footbridge over the freeway, while the other two were pitched over a fence from nearby Brandon Park Drive.

Shortly after, another Molotov cocktail was thrown at a house in Glen Tower Drive, Glen Waverley, in Melbourne's east.

The home's resident was awoken by a loud smash and went outside to find a small fire outside the front of the house.

The man put out the blaze with a garden hose and notified police.

Anyone with information is asked to call crimestoppers on 1800 333 000.