Arson attempts were made on the homes of two related families in Wanganui early today.

One family's house was gutted, but they managed to escape without injury when the noise of the fire woke them.

At a nearby house in Bennett Street, in the suburb of Gonville, an attempt was made to set fire to the front door area of the home while a car and carport were destroyed.

It is believed the attacks were possibly gang related.

Wanganui senior station officer Craig Gardiner said there could easily have been fatalities.

An elderly man and his family were in the house which was destroyed.

"It was the noise of the fire that alerted them to the fact there was a fire in their home," Mr Gardiner said.

"I'd say it was either exploding windows or fibrolite in the eaves that brought their attention to it."

Mr Gardiner said the families in the two houses were related.

There was a grandfather in the house that was gutted and there were his son and a grandson down the road where the car was set alight.

"It could be gang-related and if they're targeting private families that are in bed it's a cause for concern," he said. "It's very scary from our point of view."

Mr Gardiner said the Fire Service was called out at 4am to one house in Bennett Street and en route were informed there was another unknown type of fire at another address in the street.

"We pulled up to find the house at No 6 was well involved in fire, and we had to split our resources and send another truck to No 20 where we found a car on fire under a carport and an attempt had been made to start a fire in the doorway of that house as well."

He said the elderly man and three family members had to flee for their lives at No 6.

At No 20 there were some young children and other family members -- about five people in all.

"There was some damage to the front door where they tried to pour petrol around there and ignite the porch area of that house."

The car and the carport were destroyed. Police and fire safety officers are investigating.

Wanganui has been the scene of several violent gang incidents this year.

The violence led to the city's mayor, Michael Laws, putting forward a draft by-law banning the wearing of gang insignia in public places.

The anti-gang initiative was proposed by Mr Laws following brawls between the Mongrel Mob and Hell's Angels late in February.

There was more tension in the city's main street a couple of days later when more than 20 patched Mongrel Mob members started intimidating locals.

Mr Laws said the gangs had brought a "sphere of intimidation" to the community and a by-law was quickly drafted before being approved in March by the Wanganui District Council's strategy committee.

He said the council was determined to make the city safe and happy both for locals and visitors.