MAJOR donors to political parties in this federal election will be able to keep contributions secret for another 18 months under campaign finance laws that keep voters in the dark.

Donations of more than $11,500 made to parties in a financial year are not disclosed until February the next year, meaning contributions given now will not be on the public record until February 2012.

And despite parties claiming tens of millions of dollars in public funding, they are able to keep their campaign spending largely a secret.

Under Australia's political funding laws, candidates are required to submit a publicly accessible return that specifies the amount raised during the campaign, the amount received in donations and the identity of those who donate more than $11,500.

But in a loophole exploited by the major parties, donations and expenses linked to the party rather than the individual candidate only need to be included in the annual return.