Darwin private high school Kormilda College paid the Foundation 51 company at the centre of a Northern Territory political donations probe $33,000 last year, Australian Electoral Commission documents show.

The school, however, said it had no idea it had spent any money with Foundation 51, which is being investigated by the AEC for links with the ruling Country Liberals party.

The donation was included in the AEC's release of documents showing all monies spent with political groups and parties in the past financial year.

For the second consecutive year, Foundation 51 has filed an Associated Entity Disclosure Form, which means it has functioned "wholly" or "significantly" for the benefit of the Country Liberals, according to the AEC.

That form shows Kormilda College spent $33,000 with Foundation 51.

The school's chairman Peter Jones said this was news to him.

"The board commissioned some research, the company commissioned to do that was Crosby Textor, who did the work," Mr Jones said.

"I was not aware of any links between Foundation 51 and Crosby Textor.

"In the conversation of the board, there has never been mention of Foundation 51."

The research was commissioned to help Kormilda College consider opening a primary school.

Foundation 51 director Graeme Lewis said the college's former principal approached him to undertake the research and that the school paid the Foundation 51 invoice.

"I commissioned [Crosby Textor] to do the work, part of the work," Mr Lewis said.

"I told [Kormilda College] what we would be doing, how we would be doing it."

The Labor Party has used Parliament to call Foundation 51 a CLP "slush fund", a claim Mr Lewis and the CLP has repeatedly denied.

"It's important when you're talking about declarations and returns that we need to make sure the laws are being looked after and respected," Labor secretary Kent Rowe said.

"We feel with Foundation 51 those lines have been blurred."

The AEC and Northern Territory Electoral Council (NTEC) are investigating Foundation 51.

Peter Maley gave $50k to Country Liberals while magistrate

The AEC's release of documents also revealed former Magistrate Peter Maley was the equal largest donor to the Country Liberals, giving $50,000 when he was a sitting magistrate.

Mr Maley resigned in August 2014, less than 12 months in the job, after months of criticism from Labor and the legal profession that a magistrate should not be associated with a political party.

But he said on Monday he had done nothing wrong, pointing out there were no rules affecting whether sitting magistrates can donate to political parties.

"If you're a Territorian, you're entitled to participate in the political process," he said.

"I make no apology for donating to the CLP and will so in the future."

The Country Liberals raised $1.3 million, whereas the opposition Labor Party raised $384,993 in the 2013/14 financial year, the documents revealed.

Under AEC rules, all donations above $12,400 must be identified.

Less than 20 per cent of Labor's total donations are visible, but NT Labor party secretary Mr Rowe said the party's record would become clearer when the NTEC disclosed returns next month.

"Under the AEC return it's $12,000, under the NTEC returns we do returns of $1,500," Mr Rowe said.

"We like to take money off a wide range of donors and people like that, and especially more recently, we're having more people contributing small amounts of money to us."