Stormie Mills has been making his mark on the streets of Perth for 30 years.

Once restricted to working after dark to avoid being caught, today he is a celebrated artist who has travelled the world transforming spaces.

Mr Mills is also a vocal advocate for the controversial street art movement.

"Is it snails or escargot?" he said.

"Some people might call it vandalism and others will call it art, but the important thing is, there's a discussion about it."

This week Mr Mills has been joined by more than 40 artists from Australia and overseas as part of a program called Public.

It is a celebration of urban art run by not-for-profit arts organisation Form.

Form chairman Paul Chamberlain said the event was two years in the making.

"I'm originally from Bristol in the UK and Bristol is one of the centres for urban art," he said.

"On a trip back there a few years ago, we visited a couple of different urban art festivals and one of my daughters mentioned it would be a fantastic thing to have happen in Perth."

'A more vibrant place to live'

Blank walls around the city will now be taken over by renowned street artists.

"We've got 45 artists from all over the world who've come to help us change the fabric here," Mr Chamberlain said.

"This is all part of Perth's growing-up pains and I think that a bit of urban art around the place will make it a much more vibrant place to live."

One of the visiting artists is Gaia, a 25-year-old from Baltimore in the United States.

He will create a giant mural on a wall in an inner-city car park.

"We're utilised for our transformative capacity," he said.

"We do have the ability to completely change a space and completely change how people perceive that space.

"Whether or not that's the proper perception of that space is up to the various communities that invite us to come."

Gaia said he did not think Perth was as open to urban art as other cities he has worked in.

"Perth, and maybe Australia in general, is significantly more controlled than the United States," he said.

"There's a lot more red tape to navigate and things are a lot more ordered, for better or for worse.

"But it is impressive that they would be so trusting as to welcome international street artists to come, with almost no prior experience of the city, and then copy and paste their work into this environment.

"We'll see ultimately what the reception is."

Street art welcome in Fremantle

Attitudes towards street art do appear to be shifting, at least in some parts of Perth.

Last year, the City of Fremantle approved a new graffiti policy that would see works deemed to have cultural merit preserved.

Since then, cases of graffiti have decreased by 63 per cent.

Mr Mills said other councils could take a leaf out of Fremantle's book.

Sorry, this video has expired Street art festival hits Perth ( Charlotte Hamlyn )

"I think there's a lot to be said about the care and attention that people put in to creating these works," he said.

"So if they could understand and appreciate that a bit better and perhaps relinquish some of their want to control the way our city grows, I think it would lend to the creativity and vibrancy of our city."

Unlike a lot of similar urban art festivals held around the world, the works created this week will be permanent.

Some of the visiting artists will also visit the Pilbara to take part in community art projects there and organisers are working to continue and expand the program over the next three years to cover other parts of the state.

A street festival will be held in Perth's Wolf Lane on Friday April 11 and Saturday April 12 to showcase some of the works.