Figures revealed by the Australian Electoral Commission show senators Nick Xenophon and Stirling Griff each contributed $250,000 towards their party's election campaign.

The release of political parties' annual returns also shows that Optical Superstore businessman Ian Melrose contributed $100,000 to the Nick Xenophon Team.

Senator Xenophon said that his and Senator Griff's contributions were loans, which were repaid when the party's public funding came through.

He said that his party also paid $40,000 back to Mr Melrose.

The AEC documents showed that the Liberal Party's South Australian division received almost $5 million in the last financial year — including a donation of $360,000 from resources company Aus Gold Mining.

Labor's South Australian branch received just over $2 million, with the Shop Distributive Association handing over $100,000.