Police are investigating the cause of a fire at a tattoo parlour in Newtown, the same place a police paddy wagon was allegedly torched by a former bikie boss earlier this year.

Emergency services were called to Skin Deep tattoo parlour, on King Street, Newtown, about 1.45am on Monday.

"Firefighters were able to quickly extinguish the fire and prevented it from spreading next door," Fire and Rescue NSW Superintendent Phil Lindsay said.

A crime scene was established and police were investigating the circumstances around the fire.

Newtown police duty officer Inspector Michelle Clarke said it was too early to say what caused the fire, but it was deliberately lit.

No one was injured in the fire.

In April Scott Orrock, a former Nomads bikie boss turned Hells Angel, was charged for allegedly torching a police paddy wagon parked outside the tattoo parlour.

His bail was revoked in May and he is awaiting trial on the charges.