Conservative Party leader Colin Craig loaned $1.9 million to his party for its election expenses, but this month wrote off $1.6 million of that loan as a donation.
A $1.6 million donation was disclosed to the Electoral Commission on May 18 under the law requiring donations of more than $30,000 to be declared within 20 working days.
The party's election return was also filed with the Electoral Commission on May 18 - about two months late - and it listed no donations over the disclosure threshold of $15,000 and only $11,791.50 in smaller sums.
Mr Craig said his company, Centurion Management, had paid the bills for the Conservatives' campaign totalling $1.55 million during 2011, and subsequently billed the party for the amount.
Centurion did not invoice the party until early this year - after the period for election-year returns ended. In February, Mr Craig loaned the party $1.9 million to pay it - although a formal loan agreement was not drawn up until May 17 after the auditor of the return asked for it.