Arson suspected in western Sydney bushfire

Firefighters have had a taste of what may be a busy bushfire season ahead, after a fire broke out in bushland at Colyton in Sydney’s west today.

Around three hectares of land was blackened out near Roper Road, after the small blaze at the back of a sporting field quickly turned into a bushfire, fanned by strong winds around 2.35pm.

Emergency services closed Roper Road to traffic as thick smoke blanketed the area.

"When we arrived here on Roper Road along the western flank, you could see the fire burning about 250 metres in, burning quite well," Fire and Rescue NSW's Mark Jones told 9NEWS.

Authorities do not know how the fire started, but arson is suspected.

Firefighters put in back burns to send the fire back on itself.

No properties were damaged but smoke is still lingering in the area.