ANZ and Macquarie Bank have been hauled into the Federal Court over alleged attempts to manipulate the benchmark rate of the Malaysian ringgit.

Key points: ANZ admits to 10 instances of alleged cartel conduct, fined $9m

ANZ admits to 10 instances of alleged cartel conduct, fined $9m Macquarie faces a $6m fine

Macquarie faces a $6m fine Macquarie trader regularly contacted ANZ traders about submissions for Malaysian ringgit fixing rate

The action taken by the Australian Competition and Consumer Commission (ACCC) alleges traders at both banks engaged in cartel conduct in attempting to influence the daily rates used for currency trading.

The allegations date back to a series of trading days in 2011.

ANZ has admitted to 10 instances of attempted cartel conduct and has submitted to the court to pay a penalty of $9 million and contribute to the ACCC's costs, while Macquarie is facing a $6 million penalty and costs.

Both banks have accepted a series of facts the ACCC has put before the court.

These include that a Macquarie trader regularly contacted traders from ANZ and other Singapore-based banks in private online chatrooms about daily submissions in relation to the benchmark rate for the Malaysian ringgit.

"On various dates in 2011, traders employed by ANZ and the Macquarie trader attempted to make arrangements with other banks that particular submitting banks would make high or low submissions to the Association of Banks in Singapore (ABS) in relation to the ABS Malaysian ringgit fixing rate," the ACCC said.

While Macquarie was not one of the banks authorised to make rate submissions to the ABS panel, the trader often initiated discussions with panel traders, including those from ANZ.

The ACCC pursued the banks via the cartel provisions under the Competition and Consumer Act.

"I personally believe that the action we've taken today will send a message to the boardrooms and senior managers of banks that I think will help shape behaviour," ACCC chairman Rod Sims told ABC News.

"They did have this action brought to their attention, they acted in relation to the individuals and acted in relation to future compliance policies.

"I think we need to be clear that this occurred in 2011, that's a long time ago, and I think the banks would argue with some justification that they're trying to address the issues that have been brought to their attention."

ACCC estimates turnover on forward contracts worth $10b

The ACCC estimated the 2011 turnover in Australia for trades in the Malaysian ringgit forward contracts the traders were seeking to manipulate was approximately $9 to 10 billion.

"ANZ and Macquarie's customers included Australian companies," the ACCC noted.

The ABS benchmark rates are used as reference rates for settling non-deliverable forward contracts (NDFs) and, given they are not widely traded outside Singapore, rates must be set by a panel banks submitting their views on the appropriate rate each day.

"ANZ has agreed the employees unsuccessfully attempted to influence the setting of benchmark rates used to settle NDF contracts for the Malaysian Ringgit on 10 occasions in 2011," ANZ said in a statement.

"The three employees involved are no longer employed by ANZ."

ANZ's chief risk officer Nigel Williams said the bank has an obligation to ensure its staff, both in Australia and overseas, comply with the law at all times.

"While there is no evidence that FX (foreign exchange) benchmarks in Singapore were successfully influenced, we accept responsibility and apologise for the actions of our former employees," Mr Williams said.

"We have made significant improvements to our compliance, training and monitoring systems to ensure this does not happen again."

The rate rigging allegations are similar to a number of cases the Australian Securities and Investments Commission (ASIC) is pursuing against NAB, ANZ and Westpac over the rigging of Australia's bank bill swap reference rate, or BBSW, dating back to 2012.

In August, NAB, ANZ and Macquarie were named in a class action launched by two US-based fund managers against 17 international banks and broking houses involved BBSW trading in the US.