Anti-corruption researchers say the “the time is now” to create a strong and independent federal integrity body, after new research showed most Australians believe federal politicians are corrupt.

Researchers with Griffith University and Transparency International this week released the latest global corruption barometer, an annual survey measuring trust in governments of all levels.

About 85% of respondents said they believed some, most or all of the federal members of parliament were corrupt, a nine percentage point increase from the previous year.

Trust in all levels of government was also down. Only 46% of those surveyed said they trusted federal and state governments a “great deal” or a “fair amount”.

The study suggests many respondents had personally witnessed corruption within government. About 45.6% of respondents said they had witnessed or suspected officials having unexplained income beyond their public salary in the last 12 months.

Almost two-thirds said they had seen or suspected officials using their position to benefit themselves or their family, and 56.3% saw or suspected officials make decisions to favour “a business or individual who gave them political donations or support”.

The survey also showed two-thirds of Australians support the creation of a federal anti-corruption body, an idea resisted by the Coalition but supported by Labor.

Support for such a body was greatest among those who had worked in federal government.

A separate position paper released by Griffith University researchers on Tuesday mapped out a path to the establishment of a strong, independent federal corruption commission.

“Despite the complexity, the time is now for government to chart how it will return from a position in which it is too often forced to look over its own shoulder for fear of unaddressed integrity risks,” the paper said.

It described the current system as weak and marred by significant gaps, and let down by a lack of resourcing. It also “lacks a clear overall gateway” and support for whistleblowers.

The paper found the most strategic areas of corruption were left unsupervised, including law enforcement, where only a small number of agencies fell under the remit of the Australian Commission for Law Enforcement Integrity.

The enforcement of parliamentary and ministerial standards was weak and inadequate, the paper found.

The paper considered three options to strengthen the system: an Integrity and Anti-Corruption Coordination Council, a federal Independent Commission Against Corruption, and a custom-built Commonwealth Integrity Commission model.

The paper heavily favoured the custom-built integrity commission and found it would cost the commonwealth about $110.8m per year in both staffing and capital costs.

“This would lift commonwealth expenditure on core public integrity agencies from a notional 0.033% to 0.07%; and Australia’s total expenditure to 0.096%,” the paper found.

That was roughly the same expenditure of the weakest Australian state jurisdiction. It was “approaching” the amount New Zealand spends on anti-corruption.

The body would constitute a “best-practice independent, broad-based public sector anti-corruption commission”. It would build on the strengths of state integrity commissions but have a broader range of functions. Such a body would also involve a direct expansion of parliament’s integrity system.

Serena Lillywhite, the chief executive of Transparency International Australia, said the Australian public clearly believed the risk of “undue influence” was real and “driving increasing corruption concerns”.

“For 56% of respondents – equating to over 10.2 million Australians – to say they had personally witnessed or suspected favouritism by a politician or official in exchange for donations or support is nothing less than shocking,” she said.

“This snapshot also shows the case for a strong, comprehensive federal anti-corruption agency is well understood by those within government, not just based on the fears of outsiders.”