Prime Minister Malcolm Turnbull declared he wanted to see more transparency in Australia's political donations system - but just moments later refused to talk about his own contribution to the Liberal Party's election campaign.

While reports have suggested Mr Turnbull donated as much as $2 million to his party's re-election fight – a claim the Prime Minister has never denied – there is no sign of the contribution in the latest Australian Electoral Commission returns.

It's now believed the donation must have come after June 30, meaning it will not be detailed until this time next year - 20 months after polling day.

Delivering an address at the National Press Club in Canberra, Mr Turnbull was pressed about his views on the donations system and said he would have no objection to changes, such as real-time reporting to improve transparency and public trust.