Anonymous Facebook pages are paying to push unsourced pro-Liberal advertising into the feeds of Australian users, prompting warnings from the electoral watchdog on day two of the campaign.

Guardian Australia is tracking the use of Facebook advertising by all major parties over the next six weeks, aiming to shed light on a space that remains largely unscrutinised despite its importance to modern political campaigning.

In the opening days of the official election campaign, an anonymous Facebook page named “Our Vote Our Community” began spreading paid ads to targeted users. The page has just two followers but pays to spread slick graphics and video to a larger, more targeted audience.

The ads rail against Labor’s franking credits policy and talk up the Coalition’s addition of cancer medicine to the Pharmaceutical Benefits Scheme.

It’s unclear who is behind the page. It is unsourced and not obviously linked to a particular Liberal branch or candidate. The ads carry Liberal party branding and link to the Liberal party’s website, and videos posted to the page end with authorisations by Liberal party members.

Another Facebook page named “Gellibrand FEC Liberal Party”, an apparent reference to a local Victorian branch, was also found to be pushing unsourced political ads falsely claiming Labor planned to introduce a “car tax”.

“Bill Shorten’s new Car Tax will increase the cost of Australia’s most popular cars. Is your car on Bill’s hit list?” it said. The ad is being run across other Liberal party Facebook pages, including the party’s main page.

A screengrab of an ad running on the ‘Our Vote Our Community’ Facebook page. Photograph: Facebook

Another ad equates changes to emissions standards proposed by Labor with a $5,000 rise in the cost of new cars, relying on contested analysis. A third spruiks the Coalition’s planned infrastructure investments.

Neither the “Our Vote Our Community” or the “Gellibrand FEC Liberal Party” ads carry the legally required authorisations, either on the Facebook page or alongside individual posts.

The “Gellibrand FEC Liberal Party” page was taken down following queries by Guardian Australia.

The law requires Facebook political advertising to be properly authorised so that Facebook users can discern who is behind the content. The law helps stop hidden actors from improperly influencing voters and ensures that an individual can be held responsible for political communications. It also helps electoral authorities track political advertising and enforce the law where necessary.

The law is particularly important on Facebook, where political ads are difficult to track and scrutinise, given the nature of the medium. Facebook’s handling of political advertising has been the subject of repeated controversy, including during Brexit and the Trump presidential campaign.

One of the paid ads being spread by a Facebook page that appears to be associated with the Liberal party. The ads were not properly sourced, as required by law. Photograph: Facebook

Facebook has tools available that have been used in many countries to increase the transparency around political advertising, such as an approval process for those who want to run political ads, enforcing disclaimers on the ad detailing who funded it, and making political ads searchable in a central archive.

Facebook has chosen not to implement these transparency features for the Australian election, saying they will not be available until June when they will be globally available. Facebook has, however, temporarily banned “political” ads from being bought by non-Australians during the election campaign.

The Australian Electoral Commission said on Monday it planned to contact the “Gellibrand FEC Liberal Party” page’s authors to remind them of their obligations.

“The Facebook advertisement provided by the Guardian is an electoral advertisement that must be authorised,” a spokesman said.

The AEC said such authorisations were best embedded in an electoral image, meme, or video, so that they accompany the multimedia wherever it is later shared.

Authorisations can also be included on the Facebook page in the “about section”, the spokesman said.

“Where this is found not to be the case, the AEC will, in the first instance, make contact with the party and ask it to authorise or remove [the] Facebook page.”

Guardian Australia contacted the individual Facebook page – named Gellibrand FEC Liberal Party – and the Liberal party campaign headquarters for comment.