Multinational pharmaceutical companies are unable to assure Australians they are not being "ripped off" on the price of medicines as a result of their complex global supply chains.

The Australian heads of nine of the biggest global drug suppliers were forced into the embarrassing admission on Tuesday after backing themselves into a corner by insisting they have no idea what their own sister companies in other countries pay to import the same medicines.

At a fiery public hearing of the Senate's inquiry into corporate tax avoidance, evidence emerged of the same "double Dutch" corporate structures used by tech companies.

For more details, go to: http://www.smh.com.au/federal-politics/political-news/drug-companies-wont-deny-australia-is-being-ripped-off-on-medicines-20150701-gi2fnz.html