Australia has been singled out for its deteriorating position as it continues a four-year slide down the International Corruption Index.

Key points: Australia ranked 13th of 136 countries in International Corruption Index

Australia ranked 13th of 136 countries in International Corruption Index Australia has slid six positions since 2012

Australia has slid six positions since 2012 Lack of action by successive governments blamed for the slide

Each year Transparency International gathers assessments and surveys business people to rank 168 countries by their perceived levels of public sector corruption.

Australia ranked 13th in the latest report, dropping six positions since 2012.

Figures released for 2015 show Denmark led the rankings, followed by Finland and Sweden, with New Zealand in fourth place.

The incoming chairman of Transparency International's Australian subsidiary, TI Australia, Anthony Whealy QC, said lack of action by successive governments to curb public sector corruption was the reason Australia continued to slide down the rankings.

"The delay in responding to these issues has now made reform critical and a commitment to ramp up efforts to tackle foreign bribery, which has particularly impacted perceptions of Australia, is now urgent," Mr Whealy said.

Those perceptions are not helped by the uncovering of large scale corruption linked to Australia's most reputable institutions, including the Reserve Bank.

Two firms owned by the RBA, Securency and Note Printing Australia, were charged with bribing foreign officials to win banknote contracts in 2013.

The scandal continues to taunt Reserve Bank governor Glenn Stevens as questions are raised about what he knew about Securency's alleged corruption involving up to $17 million paid in bribes.

TI Australia CEO Phil Newman has called on the Turnbull Government to deliver a stronger federal anti-corruption agency.

"With Australia's worst foreign bribery offences having been committed by former or current government-owned entities - the Australian Wheat Board, Note Printing Australia and Securency Limited - there is no excuse not to have implemented all of the OECD's reform recommendations in this area by the end of the year," Mr Newman said.

The inflow of illicit foreign funds into Australia's property market is also cited as a problem.

Mr Whealy said unless Australia strengthened its anti-money laundering regime it would continue to fall in the corruption rankings.

"The illicit flow of funds into Australia and particularly from Asia is a very significant problem and we need to have proper laws to vet it, transparency, and we need to have sanction to ensure that it doesn't happen," Mr Whealy said.

"We need to have better vision and control of where money is coming from."

The 2015 report found "68 per cent of countries worldwide have a serious corruption problem" and "not one single country anywhere in the world is corruption free".

The report shows Greece, Senegal and the UK are among the improvers and North Korea and Somalia are at the bottom of the corruption index.