A bank raising its interest rates to follow a competitor's move is tantamount to price signalling, according to the Australian Competition and Consumer Commission (ACCC).

This proposition emerged as the Senate Economics Committee continued on Tuesday its investigation on the country's banking competition and this time around, ACCC chair Graeme Samuel suggested that ANZ Banking Group Ltd may be guilty of price signalling.

The idea stemmed from the exchanges between Samuel and Senator Annette Hurly when the latter pressed the ACCC head to comment on ANZ chief executive Mike Smith's testimony before the Senate panel, in which he reportedly stated that moving up interests rates is a matter of not getting left behind by rival banks.

Senator Hurly queried Samuel if the ANZ chief's words could be taken as leading to price signalling and the ACCC head replied in the affirmative but he quickly reminded that even if such is the case, stamping out the practice for now is beyond the powers of the competition watchdog.

Also, the ACCC informed the panel that price collusion is far different from price signalling though it admitted that in terms of competition question, "it has exactly the same outcome."

Samuel noted that even if the government went ahead with its plan to prohibit price signalling, market players would not be deterred from discussing among themselves policy rates decisions as he suggested that price competition would be better off in a market where "the uncertainty associated with the true competitive tension is absent."

The ACCC head said that banning price signalling would not redound to direct benefit for banking clients as he stressed that "consumers of bank products would be more concerned with interest rates over the long term than next week's interest rate move by the banks."

Samuel also clarified that the ACCC is now averse on the notion of bank mergers, which he said was a mere misinterpretation of an earlier assessment from the regulatory body. Mergers in the banking industry could still occur but asserted that future initiatives on the subject would be handled by the competition watchdog in a more cautious and conservative manner.

The ACCC head also dodged attempts by the Senators to lure him into speculating whether approving the merger between Westpac and St George was the right decision made by the body, with Samuel merely remarking that the presence of a financial crisis could be a relevant factor for their decision.

Yet he hastened to add that even if a crisis is apparent, the likelihood of an entirely different decision on the merger is very remote, adding too that "I cannot say whether there'll be another merger."

Mergers, according to Samuel, are decided on the question of competition capability and he pointed out the obvious by saying that definitely regional banks could afford to clash head-on with Australia's four major banks.

In the event of a mistake on a merger decision, the ACCC said that corporate marriages can still be dissolve within three years especially in cases where the regulator has been misled and this can be argued before the Federal Court.

Samuel maintained too that stability is attached with appropriate regulation, which should be enough to ward off the negative impacts of both market monopoly and uncontrolled competition.