The Australian Securities and Investments Commission (ASIC) has confirmed its interest rate rigging investigation is targeting a number of major banks.

ASIC said on Friday it was taking Federal Court action against ANZ for allegedly manipulating the bank bill swap reference rate (BBSW), which affects commercial and personal loan rates.

In a statement on Friday, ANZ rejected all of the allegations and said it would "vigorously defend legal action".

Law firm Maurice Blackburn has confirmed it is looking into a possible class action against ANZ over allegations of interest rate rigging.

The corporate regulator said in a brief statement this morning that its investigation is broad and involves a number of major banks.

The BBSW is the primary interest rate benchmark used in the Australian financial market and is the rate at which banks lend to each other and is the reference point that is used to set interest rates on most business loans, and indirectly helps to set personal lending rates.

ASIC has been investigating potential rigging of the BBSW since 2012.

It has already secured voluntary contributions of $1.6 million from the Royal Bank of Scotland, and $1 million from UBS and BNP Paribas after those banks discovered "potential misconduct" in their BBSW submissions.

ASIC chairman Greg Medcraft urged banks involved in manipulating the BBSW to "plead guilty", during a Senate Estimates committee hearing last month.