The WA Government has revealed further details of a controversial advertising campaign run through a converted public bus, putting the value of the overall campaign at more than $170,000.

The latest information comes as the Government faces increasing criticism over its "exclusive partnership" with Seven West Media, to turn a Transperth bus into a mobile promotional vehicle spruiking its Bigger Picture projects.

The BigPic360 campaign, which debuted on the weekend outside Seven West Media's Telethon event, gives people a virtual reality look at what the Government's major construction projects will look like once completed.

Under pressure to release more information about the agreement with Seven West Media, the Premier's office confirmed the deal was worth $117,000 before GST, and detailed what was provided under that deal.

But the $117,000 figure did not include the $50,000 bill for the fit-out and signage for the bus, the $4,000 spend on further campaign marketing material or the significant costs relating to vehicle hire and paying for the driver.

That pushes the cost of the campaign above $170,000, but final estimates for the expected bus hire and driver costs have not been released.

Driver costs range from $77.41 per hour on weekdays up to $124.73 on Sundays, while the cost of hiring the vehicle from the Public Transport Authority is $2.67 per kilometre driven.

The agreement with Seven West Media, owner of both Channel Seven and The West Australian and a dominant player in the state's media market, provides for the organisation's staff to set up and operate the bus at six events and for the company to support and promote those events through its social media channels.

It also includes the translation of "up to six sets of architects' files" into the required format and for the technology, equipment and staff necessary for the events.

The Premier's office said the cost was the equivalent of approximately seven full-page advertisements in The West Australian and that the new technology was chosen because it allows flexibility and enables people who do not engage with traditional media to learn about the projects.

Seven West Media is one of Australia's biggest media organisations, owning both Channel Seven and The West Australian.

In a press release promoting the agreement last Friday, Seven West Media declared the agreement an "exclusive partnership" but the Government said it was still able to reach promotional deals with other agencies.

"The agreement is such that Seven West does not undertake any other Oculus Rift [virtual reality] projects while it is partnering with the major projects campaign," Leader of the Government in the Legislative Council, Peter Collier, told Parliament.

"In promoting major projects, the state is not bound to only deal with the Seven West group."

Seven West moves away from editorial coverage claim

The release also stated that Seven West would provide "marketing and editorial coverage" as part of the deal, a claim which the organisation's journalists have since sought to refute.

"Big thanks to @brettmccarthy for correcting digital sales dude's claim that editorial coverage was part of BigPic360 deal with State Govt," The West Australian journalist Neale Prior tweeted, referring to the newspaper's editor Brett McCarthy.

"Brett said: 'No editorial coverage of the bus was promised or was part of the advertising deal with the Government'," he continued.

Earlier on Wednesday, Mr Barnett defended the campaign, rejecting criticisms from Labor that it was a waste of taxpayer money.

"As a State Government we spend far, far less than our predecessors on advertising but what we do, we do it in a modern way and in a contemporary way," he told 720 ABC Perth.

"Just whacking an ad on television or in the paper doesn't do it, so using modern technology is what we're doing and online technology."

But Labor leader Mark McGowan attacked the promotion as a continuation of the Government's "propaganda campaign", saying it would not be repeated if the Opposition won the 2017 election.