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. 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.