LABOR is a far more ferocious prosecutor of whistleblowers and leakers than the Howard government, with Kevin Rudd overseeing a doubling of leak referrals to the federal police in his time as prime minister.

Figures obtained during a Herald investigation into federal police leak inquiries show the Howard government referred 16 leaks of government material between 2005 and 2007 and the Rudd government referred 32.

The figures mirror a shift in US politics where the more liberal Obama administration has taken a harder line on whistleblowers than the Bush administration did.

Allegations of political leaks are handled by the special references section of the federal police, but most inquiries are run by a unit within it called head office investigations, a multimillion-dollar, 17-officer Canberra group.

The section also investigates other politically sensitive matters - at present the Christmas Island boat crash last month - and most of its work is investigating leaks of Commonwealth material.