ANZ, Citi and Deutsche Bank have said they will defend the allegations, in a case that comes as the banking industry is already facing an erosion in public trust, a royal commission, and a backlash from politicians.

It is the first criminal cartel action in Australia to focus on conduct in the financial markets, in an area of the law regarded as highly technical. Although the precise allegations are not public, ANZ has said it is alleged to have been "knowingly concerned" in cartel conduct when the investment banks reached an  "understanding" over how to offload the ANZ shares after the raising.

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Some observers suggest the case will focus on whether the banks sought to restrict the supply of ANZ shares, in order to keep the price higher. Citi last week responded to such a claim by saying it needed to be seen against the fact hundreds of millions of dollars in ANZ shares were traded every day.

Companies face maximum penalties of 10 per cent of annual turnover, or three times the benefit gained from criminal cartel behaviour, while individuals can face up to 10 years' jail if they are found guilty.

Citi has said the case deals with a "highly technical" part of the law that had not previously been addressed in guidance notes, but experts said CDPP would only bring criminal charges if it had a reasonable case.

Unlike other high-profile cases against the banks, it is expected the case would be tried before a jury.

The evidence against the banks is not known, but the ACCC can ask the Federal Police to use phone taps and other surveillance techniques in some cartel cases, according to the regulator's website.

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The case is tipped to have major implications for how investment banks carry out capital raisings, and news of the action reignited calls for reform of the current system, which critics say favours big shareholders over small investors.

Australian Shareholders' Association director Stephen Mayne said the charges against ANZ presented an opportunity for "serious reform" of the capital raising system used by large listed companies. It wants to see  the elimination of institutional placements – where companies run a book build to issue new stock to big investors.

"We see this is a big opportunity for meaningful reform of the book build system," he said. "Hopefully this is the final nail in the coffin of ASX100 placements."

The ASA is pushing for possible legislative reform, and for boards of directors to steer clear of institutional placements, which Mr Mayne described as a "black box" process that showed no respect for existing shareholders in a company. When it ran the placement, ANZ also offered retail shareholders the opportunity to buy discounted stock through a share purchase plan.

Mr Mayne could not recall another top 10 ASX company since 2010 undertaking an institutional placement. On Friday ANZ revealed there had been a shortfall of almost $800 million, an amount that was picked up by the investment banks, and Mr Mayne said the bank should apologise for not disclosing this fact at the time of the raising in 2015.

"Who on earth thinks they can hide an $800 million shortfall – the biggest shortfall in Australian history? Come on."