The former HSBC employee who leaked sensational secret documents alleging the bank helped wealthy customers - including Australia's Kerry Packer - dodge millions of dollars in taxes has warned that the revelations are just the "tip of the iceberg".

The files created global shockwaves on Monday, spotlighting the financial dealings of the world's ultra-rich and prompting British MPs to launch an inquiry into the London-based bank.

The cache of files made public in the so-called SwissLeaks case includes the names of celebrities, alleged arms dealers and politicians - though inclusion on the list does not necessarily imply wrongdoing.

Published at the weekend, the files claim HSBC's Swiss division helped clients in more than 200 countries evade taxes on accounts containing €104 billion ($A150.89 bn).