The head of PwC in Australia has resigned as chief executive three days after admitting that he had received emails regarding confidential government information on changes to tax avoidance laws to win new business.

Tom Seymour, chief executive of PwC Australia since March 2020, has stood down with immediate effect following a discussion with the board of partners on Monday. Kristin Stubbins, its head of assurance, will serve as acting chief executive.

“We have agreed with Tom that it is in the best interests of the firm and our stakeholders,” said PwC.

Tracey Kennair, chair of the board of partners, said PwC immediately needed to rebuild and enhance trust in Australia, one of its largest markets, where it has launched a review of its practices in the country.

“The independent review previously announced, in addition to the changes already made, will help us meet this objective,” she said.

PwC has been embroiled in a scandal since February when the Tax Practitioners Board, the industry watchdog in Australia, banned Peter-John Collins, PwC’s former head of international tax in Australia, for circulating information with other PwC staff from confidential meetings with the Treasury over new laws designed to curb tax avoidance.

Emails released by a Senate committee last week revealed that PwC had used the confidential information provided by Collins, who had signed strict non-disclosure agreements, to advise its clients and win new business.

Seymour, who was managing Collins when he ran the Australian arm of PwC’s tax division, admitted on Friday that he was one of a number of partners who received some of the emails regarding the financial success of the tax advice in 2015 and 2016.

The emails showed that the information was shared with colleagues in the UK, Ireland and US and the emails contained praise for the “accuracy” of Collins’ advice in winning millions of dollars worth of new business in North America. The Australian tax partners had worked “extensively” with other PwC offices around the world, including in the US, Netherlands and Singapore, one email said.

Australia is one of PwC’s biggest global partnerships reporting A$3bn (US$2bn) worth of revenue in its most recent financial year. The unit counts the Australian government as its largest customer.

Some Australian politicians have called for the Treasury to sever its ties with PwC. The auditor’s partners will vote on a new chief executive in the coming months.

Stubbins said in a statement: “We are committed to learning from our mistakes, listening to our stakeholders and enhancing our culture to build stronger trust and transparency.”