By Lewis Jackson

SYDNEY (Reuters) -The chair of an Australian senate committee looking into PricewaterhouseCoopers' leak of a confidential government tax plan has called for an international investigation into the matter.

Committee chair Senator Richard Colbeck presented a 33-page report on the leak to parliament on Wednesday and said information released to date showed the scandal "extended internationally" and said other countries should begin their own investigations.

"This was something that was being worked on, negotiated, globally," he said. "There's no doubt in my mind that other jurisdictions should be looking at this matter... it would be in their interests to do so."

Australian tax authorities have found that a former partner in the firm who was advising the federal government on laws to prevent corporate tax avoidance shared confidential information with colleagues which was then used to pitch to multinational companies for work.

Earlier this month, PwC Australia listed in an unpublished letter to the senate committee at least 67 current and former staff who may have known of the 2015 leak of confidential government tax plans.

But the report, titled "PwC: A calculated breach of trust", said the onus was on the firm to go public with the full details of those involved and accused the firm of a years-long deliberate cover-up.

"Is PwC's internal culture so poor that its senior leadership does not recognise right from wrong, and lacks the capacity to act in an honest, open, and straightforward manner?" the report said.

PwC, one of the world's "big four" audit and advisory firms, will consider the report's content and await the government's response, a spokesperson said.

Acting CEO Kristin Stubbins apologised for the leak on behalf of the firm in an open letter last month.

In response to the scandal, four major Australian pension funds that collectively manage around A$750 billion ($510 billion) froze new work this month and a number of government agencies, including the central bank, have said they will pause or review contracts with the firm.

The report also called on PwC to cooperate fully with a current Australian Federal Police investigation.

($1 = 1.4778 Australian dollars)

(Reporting by Lewis Jackson; Editing by Edwina Gibbs)