By Lewis Jackson

SYDNEY Westpac Group, Australia's fourth-largest bank by market capitalisation, on Wednesday cut ties with scandal-tainted auditor PricewaterhouseCoopers (PwC) Australia, ending a relationship stretching back to 1968.

The audit and consulting major has been under fire this year after revelations a former partner leaked confidential government tax plans and used them to win work with global companies looking to restructure their Australian tax affairs.

Westpac said on Wednesday it would tender for a new external auditor as part of "best practice for audit firm rotation".

The two-paragraph statement did not mention the tax leaks issue or reasons for the timing of its decision. A spokesperson did not immediately respond to questions from Reuters.

PwC has audited Westpac since 2002, before which PwC partners and their ancestor firms had audited the bank since 1968.

Australia requires auditors spend no more than five consecutive years out of seven on a company, though auditing firms can remain for longer periods by rotating staff involved.

However, PwC's lead Westpac audit partner assumed the role less than two years ago, in December 2021, according to a Westpac governance statement this month.

A PwC Australia spokesperson said the firm understood the board's decision and was proud of its time as Westpac's auditor.

Westpac paid PwC about A$34 million ($22 million) in audit and audit-related fees in financial year 2023, roughly 1% of the local consultancy's A$3.4 billion in revenue that year.

Since coming to light in January, the tax plan scandal has forced out PwC Australia's chief executive and a string of senior partners, prompted public- and private-sector clients to freeze ties and entangled big-name customers including Alphabet's Google, Uber Technologies and Facebook owner Meta Platforms.

($1 = 1.5555 Australian dollars)

(Reporting by Lewis Jackson; Editing by Christopher Cushing)