Federal police are investigating 16 allegations of Australians bribing foreign officials.
The Organisation for Economic Cooperation and Development's latest anti-corruption report notes a surge in AFP cases over the past 2½ years, saying the number of investigations peaked at 17 in December 2014, up from seven two years earlier.
Only two cases – those involving Reserve Bank note-printing businesses Securency and NPA, and Sydney construction firm Lifese – have yet reached court.
A federal police spokeswoman said on Tuesday the agency did not comment on ongoing investigations.
However, the OECD expressed frustration with the secrecy surrounding Australia's anti-bribery efforts, saying suppression orders in the Securency case continued "to prevent in-depth discussion" of Australia's international anti-corruption obligations.
Greens senator Lee Rhiannon called for law-enforcement agencies to be more open, saying discussing bribery problems publicly was part of the solution.
"We need to change how things are done and how things are perceived to be done," she said on Tuesday.
"I'm particularly conscious of this coming from NSW, where people are increasingly cynical about engaging with the democratic process.
"What we're talking about here – suppression orders on possible corruption charges – is all part of the mix ... It just adds to a belief that there are cover-ups of such matters."
The OECD report also urged Australia to better protect private-sector whistleblowers, recommending they be given the same protections as public servants who exposed misconduct.
The federal government agreed last year to establish an "office of the whistleblower" within corporate watchdog ASIC.
However, a recent Transparency International report found Australia lagged well behind many other G20 nations in protecting business whistleblowers. Australia's corporate laws failed to rate "green" – or comprehensive – in any of the 14 areas assessed in the report.
Senator Rhiannon said stronger protections were crucial for employees who outed corrupt practices.
"These people are, in by far the majority of cases, very courageous. They take risks that can impact on their personal lives, their mental health – it can be an enormous step," she said.
"Having an office of the whistleblower can not only provide protection but give these people more dignity."
Federal Justice Minister Michael Keenan tabled new legislation last month to close a loophole in foreign bribery laws, which potentially allowed Australians to hide behind intermediaries.