Here's how much was donated, and spent, on the Voice referendum

The Australian Electoral Commission released financial disclosures from donors and campaign groups on Tuesday, detailing the different camps' spending and income during the referendum period.

But with smaller donations flying under the $15,200 disclosure threshold, many of the sources backing the two camps remain unknown, renewing calls for greater electoral transparency.

The data shows that Australians for Indigenous Constitutional Recognition - the key fundraising vehicle that ran the Yes23 campaign - received more than $47 million in donations

Entities only had to declare donations made after the electoral commission's referendum reporting period began on March 11.

The University of New South Wales, home to the Uluru Dialogue, declared more than $11 million in donations.

The two entities spent more than $50 million in the campaign: Australians for Indigenous Constitutional Recognition spent $43.8 million, and UNSW $10.3 million.

Donations were also made to several other smaller advocacy organisations, groups and individuals campaigning for the "yes" and "no" camps. These included activist group GetUp, various Liberal Party state divisions, and independent MPs such as Allegra Spender and Dr Monique Ryan.

The Paul Ramsey Foundation appears to have been the single largest benefactor in the referendum, donating more than $7 million to Australians for Indigenous Constitutional Recognition.

Corporate Australia also represented some of the biggest contributors. ANZ Bank, the Commonwealth Bank, Woodside Energy, Westpac and Woolworths Group poured millions into the "yes" campaign.

Former prime minister Malcolm Turnbull is also listed as having donated $50,000 to Australians for Indigenous Constitutional Recognition.

Meanwhile, Australians for Unity - the merger of the Recognise a Better Way and Fair Australia campaigns against the Voice - received almost $11 million in donations.

Conservative lobby group Advance Australia received $1.3 million. But despite this, the two entities spent $11.8 million and $10.4 million on the "no" campaign, respectively - the second and third highest spenders in the referendum reporting period.

The "no" campaign appeared to rely more heavily on smaller donations from individual contributors.

Silver River Investment Holdings - run by former fund manager Simon Fenwick - donated a quarter-of-a-million to Australians for Unity, as did the Riley Street Car Park Pty Ltd, Harbig Properties Pty Ltd, and Mr Fenwick himself.

The B Macfie Family Foundation gave $800,000 to the campaign, in eight individual $100,000 donations to Australians for Unity. Its director, Bryant Macfie, donated an extra $100,000 to the "no" campaign.

But while Advance Australia has declared the total donations it received and money spent on the referendum, the data doesn't reveal which individuals or entities contributed to its campaign.

This is likely because these individual donations sat below the $15,200 threshold. Entities are only required to provide details for any donations made above this amount.

This threshold means that the sources behind millions of donations across the referendum campaigns are hidden as, what the Australian Democracy Network calls, "dark money".

In saying that, elsewhere on the electoral commission's website, Advance Australia is listed as a recipient of four donors. The Canberra Times understands the electoral commission is enquiring into these discrepancies.

Analysis by the network has found that while entities declared receiving a total of $79.6 million in donations, the source behind $16 million of this funding remains hidden - around 21 per cent.

The network also found that while Australians for Indigenous Constitutional Recognition disclosed the source of over 90 per cent of donations, Australians or Unity disclosed less than half of their donations.

Ray Yoshida, campaigner at the Australian Democracy Network, said this was "another reminder why we urgently need greater transparency in our elections".

"The fact that an organisation can spend over $10 million influencing voters and not disclose a single cent of where that money came from is beyond belief," Mr Yoshida said.

"The easiest way to fix this is by lowering the donation disclosure threshold to $1000. The federal Labor party has been committed to this for decades, it was an election promise from Labor, and yet the government is now saying that we may not see this change until after the next election."