Two taxi drivers have been assaulted in separate attacks in western Sydney overnight.

The first driver was allegedly robbed and assaulted by his three passengers in Bangor Street, Guildford around 8pm last night.

His cab was stolen, but discovered a short time later in nearby Parker Street on fire.

The taxi driver was taken to Westmead Hospital with minor injuries.

Police are seeking three men described as being of Pacific Islander in appearance, aged between 20 and 25, two being of a large build and the third slim.
 
In the second incident, a cabbie was assaulted and robbed in Willar Street, Merrylands around 8.15pm.

The driver was dropping two men in the street when the taxi was approached by a third man. The passengers and third man then allegedly assaulted the driver before making off with a sum of cash.

They were last seen running west from Willara Street.

The driver was not injured.

The three men are described as being of Pacific Islander in appearance, aged between 20 and 25. Two were of solid build and one was of medium build.

One man was wearing a grey T-shirt with yellow stripes. A second man was wearing a black T-shirt.

Investigations are continuing.