Australia's three biggest newsmedia groups are backing a national campaign to stress the value of trusted journalism to advertisers.

NewsMediaWorks foundation members News Corp Australia, Fairfax Media and Seven West Media are behind the coordinated advertising campaign, developed by Thinkerbell to target advertisers and agencies.

It will appear across all metro and national print and digital news media, plus most regional and community titles, and asserts why trusted journalism is important for advertisers. Slogans include 'It's what's on the other page that makes this space so powerful', 'For why this ad works, see above' and, in digital, 'Surround your brand with articles your customers trust.

The campaign points to website thetruthbuildstrust.com.au which directs advertisers and agencies to an AdTrust study, in which Galaxy Research found that that only 22 per cent of people trust what they read in social media, and newspapers were the most trusted media for both content and ads.

News Media Works chief executive Peter Miller says "the company you keep defines you, and it's the same for brands and the context within which they choose to be seen".

"Journalism is what draws readers to our trusted news brands."

The campaign launches at a time when there is substantial uplift in advertising expenditure in print news media. The most recent SMI August figures show double-digit growth in metropolitan newspaper spend and growth for newspapers overall.

Print spend grew 2.7 per cent year-on-year, attributed to the 11.1 per cent increase in agency spend in metro titles. Regional papers also experienced growth, according to the latest figures.