Policy think tank the Grattan Institute has found a quarter of the public money used for federal government advertising is used to fund politicised messages.

It said federal governments of both major parties spent $630 million since 2008 on advertising that promoted government achievements or sought political advantage in other ways.

The think tank used the findings, released in a new report on Sunday, to call for stronger rules stopping governments from spending public money on politicised ads.

"Using taxpayer-funded advertising to seek political advantage by including party slogans or colours, spruiking government achievements, or deliberately timing campaigns to lead into elections should not happen," the report said.

"Yet such misuse of taxpayer-funded advertising is rife."

The report found two of the five largest government ad campaigns each year since 2008 were politicised, including ads last year that promoted Coalition economic policy.

About $50 million of the nearly $200 million spent each year by federal governments on advertising went towards politicised campaigns, it said.

The trend occurred across both Labor and Coalition governments, which each approved five of the 10 most expensive politicised federal campaigns, the report said.

The institute aimed criticism squarely at the new Labor government, too, saying it had weakened controls against politicised ads by scrapping a regulatory committee in July.

Australia had weak protections against government spending on politicised ads, the report said.

"Government advertising campaigns should be allowed only where they are necessary to encourage specific actions or drive behaviour change," it said.

"Campaigns that promote government policies or programs, without a strong call-to-action, should be prohibited."

Among the reforms the institute recommended was an independent panel to assess government ad campaigns before they are launched and with power to reject them if they are politicised.

Governing parties should reimburse the public for the costs of government ad campaigns found by audit offices to subvert the rules, the Grattan Institute said.

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It also recommended campaign messages should be instructive, and spending should be proportionate to the purpose of the ads.

Ad campaigns should be timed to run when they will be most effective - rather than for electoral advantage, the report said.

An analysis by the think tank of federal government advertising since 2008-09 found politicised ads usually included political statements, party slogans, or overt party colour schemes.

Governments spent $80 million over the past 13 years on campaigns that promoted political parties, it said. Newspaper advertising this year used a colour scheme similar to the Liberal Party blue alongside a vague statement promoting the Morrison government's economic policy, the report said.

The analysis also showed government advertising spiked in the months before federal elections, and that pre-election ads contained messages that looked politically-motivated and promoted the incumbent's policy platform on major election issues.

About $580 million, or 20 per cent of spending on government advertising campaigns, went towards ads that created a positive image of the government's performance but lacked a strong call to action, it found.

The government spent about $85 million of public money on politicised advertising campaigns in the lead-up to the 2019 federal election - a figure on par with the combined spend by political parties on TV, print, and radio ads, the report said.

Grattan Institute chief executive Danielle Wood said "weaponising" taxpayer-funded advertising for political advantage wasted public money, undermined trust in politicians and democracy, and created an uneven playing field in elections.

"Sadly, our report shows that Australians cannot rely on the goodwill of ministers to prevent misuse of public money on politicised advertising," she said.