THE Australian government had long-standing suspicions that a Reserve Bank company was using a foreign intelligence officer as a sales agent, but continued to deal with him, a court has heard.

Austrade's former senior commissioner to Vietnam, Patrick Stringer, was cross-examined yesterday during a committal hearing involving eight former Reserve Bank company executives accused of false accounting or conspiring to bribe foreign officials to win banknote contracts.

When asked about a 2007 Austrade report stating that Securency agent Colonel Anh Ngoc Luong had "probable" links to the Vietnamese intelligence service, Mr Stringer said: "We had known - we the embassy had had suspicions of his status for many years."

Mr Stringer, who was posted in Vietnam between 2006 and 2008, was asked whether the source of those suspicions was rumour or something more credible, and he said: "More concrete information."

"In places like Vietnam evidence is very hard to come by," he said, and to make further inquiries would not have been ''productive".

He said Colonel Luong's company was a Securency agent "on a commission-only basis and that was about as much as I really needed or wanted to know".

He wrote in a 2006 report to Securency, read in court by barrister Mandy Fox for former Securency managing director Myles Curtis, that: ''Very few agents would be prepared to work under such an arrangement in Vietnam. Agents felt that such an arrangement would drive their asking price up in one case by more than fivefold. Agents felt the key issue was that they would not be able to estimate their 'expenses'. This is seen as an indirect reference to illegal corruption by officials.''

When asked what he meant, Mr Stringer said he had "thought long and hard before writing that". "The fact is that certain agents will indicate that they have expenses and they often mean not just dinners or small gifts or whatever … Vietnam is a renowned market for corruption and in some cases people are not very backward about talking about it."

Mr Stringer agreed he "did not know the amount [of commission paid] and it wasn't the practice of Austrade to ask such questions".

Ms Fox asked: "Why [wasn't] that practice adopted by Austrade?'' Mr Stringer said that was a "very big question" and not necessarily one he could answer. He later said that beyond a "matchmaking" role, "Austrade is always very careful not to be involved, you know, at the very commercial end of things."

Austrade saw media reports in 2006 that Vietnamese officials would investigate reports of irregularities at its central bank in relation to Australian banknote contracts but did not believe they were trustworthy.

Mr Stringer said there had been no suggestion Colonel Luong or anyone at Securency had been involved in corruption. He said Securency was "something of a poster boy for Austrade" and Myles Curtis was "somebody that Austrade … could be very proud of" and whom he "respected enormously".

The hearing continues.