Westpac has appointed a customer advocate to review the bank's handling of complaints - the last of the big banks to do so.Adrian Ahern, a partner at Norton Rose Fulbright, will take on the role of Westpac group customer advocate, reporting to the group deputy chief executive Phil Coffey.The bank said in a statement: "The customer advocate will have the power to review and make independent, binding decisions about individual retail or small business customer complaints where customers are not satisfied with the internal dispute resolution process."An important part of Mr Ahern's role will be to recommend, where necessary, changes to policies and procedures across the Westpac group to ensure the best outcomes for customers."In August Commonwealth Bank appointed Brendan French, its head of customer relations, as its general manager customer advocacy and remediation to "provide oversight and co-ordination for how Commonwealth Bank is serving its customers across the group."The bank said its customer advocate would work for fair customer outcomes and complaints resolutions, look for areas where there was potential for customer concerns to arise and ensure that remediation is undertaken in a high quality, consistent and timely way.In July National Australia Bank appointed Catherine Wolthuizen as independent customer advocate to support its retail and business customers in resolving serious complaints.Wolthuizen has served as chair of the Consumers' Federation of Australia and as a board member of the Insurance Ombudsman Service.NAB chief executive Andrew Thorburn said in a statement: "We want to give customers confidence that when we get it wrong we will do the right thing and resolve and remediate their issues quickly."NAB appointed an independent customer advocate to its wealth division last year.ANZ has had a customer advocate since 2003, whose job is to review disputes involving retail, small business and wealth customers. The job is currently held by Jo McKinstray, who reports to the senior executive of the Australian banking division. ANZ said that over the past year 1216 disputes were referred to the customer advocate - an increase of 27 per cent over the previous year.