Mr Minz intends to step down from the CEO role when the term of his current contract concludes at the end of the year.
Heritage will advertise the CEO position nationally in newspapers and online on April 17, with applications to close at the end of May.
Mr Minz joined Heritage in 1993, initially as head of internal audit. After fulfilling a number of managerial roles, he became deputy chief executive in 2002 before being appointed CEO in 2003.
He said his decision had been made after much soul-searching and with considerable sadness. But he said he has always been an advocate of limited tenure for any CEO.
“I’m incredibly proud of what the Heritage team has achieved during my 12 years as CEO. I have been honoured to lead such a great organisation,” Mr Minz said.
“I look back with enormous satisfaction at the culture we have created and the way this organisation has evolved. Despite the GFC and a prolonged period of strong competition, we have grown to be Australia’s largest mutual bank. I leave knowing that Heritage has a proven performance pedigree and is in a very strong position.
“However, there comes a point when you know it is the right time to walk away and entrust the CEO responsibilities to the next person honoured to take on this stewardship role.
“Heritage has incredible leadership talent and an exciting future ahead. I will leave Heritage with total confidence in that future,” Mr Minz said.
Heritage chairman Kerry Betros praised his contribution to the organisation.
“John Minz has been an absolutely outstanding CEO for Heritage,” Mr Betros said.
“He has led Heritage through a period of sustained growth and modernisation, with a sharp eye on the best interests of customers and staff, while also broadening the range of products and services available to customers.
“He has done this with the greatest integrity and professionalism, and instilled a culture of engagement and service excellence among our staff.
“John will be sorely missed and I wish him and Lisa all the best in retirement.”
Mr Minz will look for non-executive opportunities to support his current charitable and community interests, including his positions on the boards of Australia’s CEO Challenge and Downlands College.