The heads of two of Australia’s biggest banks have acknowledged the institutions took too long to address misconduct that was eventually uncovered by a royal commission.

Commonwealth Bank chief executive Matt Comyn and Westpac chief executive Brian Hartzer have also admitted the banks have their work cut out for them to regain the public’s trust.

The sentiments emerged while the bosses were being grilled by federal politicians at a parliamentary hearing in Canberra.

Mr Comyn, who took up the top job at the Commonwealth Bank six months ago, said the bank had been too slow to fix customer service problems because it had become complacent.

“There have unfortunately been failures of judgment, failures of process, failures of leadership, and in some instances, greed,” he said.

“We’ve been too slow to identify problems, too slow to fix underlying issues, and too slow to put things right for customers.

“We became complacent.”

Westpac was also too slow to grapple with customer issues, particularly in its financial advice services area, Mr Hartzer said.

“We weren’t quick enough to identify and fix the problems, and we accept the consequences of this delay,” he said.

The leaders laid bare the steps the banks have taken to turn things around, with both stressing they have improved accountability by clarifying exactly what each of their senior executives are liable for.

The leaders also noted the banks have changed incentives for those working at branches.

Other reforms at the Commonwealth Bank have included strengthening lending processes and making it simpler for customers to choose products.

Heads have rolled at the Commonwealth Bank over misconduct, Mr Cormyn revealed, with 41 people sacked so far this year and nine stepping down while being investigated.

Mr Hartzer said improving the way Westpac deals with complaints has been central to its response, with a new group executive hired to oversee complaints handling.

But neither chief executive is under any illusions about how long rebuilding trust will take.

“From an overall reputation point of view, this is obviously going to take years to restore,” Mr Hartzer said.

Mr Cormyn said his bank’s recent changes are only the beginning.

“I accept that, and understand that you will judge me, and the Commonwealth Bank, on our actions.”

The hearing comes two weeks after banking royal commissioner Kenneth Hayne QC delivered an interim report, blaming greed and the pursuit of profit for the widespread misconduct in the banking and financial services industries.

ANZ chief executive Shayne Elliott will appear at the hearing on Friday, while National Australia Bank boss Andrew Thorburn will appear a week later.