The Abbott government's plan to rescind parts of Labor's tax transparency laws was justified in large part on the fears of company owners that they could be targeted for kidnap and extortion if they were forced to divulge how much tax their companies pay.

But documents requested under Freedom of Information show Assistant Treasurer Josh Frydenberg did not ask for or receive any advice from the government's own security experts, including the Australian Federal Police, to confirm those fears were real.

University of NSW financial disclosure expert, accounting lecturer Jeffrey Knapp, has called the decision "the stupidest excuse for non-disclosure I've ever heard".

The government released draft legislation for comment last week, saying that some submissions to the Gillard government's original proposal had "noted that the information could adversely affect the privacy and personal security of the ultimate owners" of companies.

But the government did not corroborate those fears. Applications to the AFP, the Attorney-General's department and the Australian Tax Office, submitted by the Transport Workers' Union, all came back saying no documents exist in relation to advice about the safety of individuals if the new regulations went ahead.

A spokesman for Mr Frydenberg pointed to a single reference to the safety of shareholders in a three-page submission by Australia's largest carpet manufacturer, Godfrey Hirst, and a submission by Ernst & Young that makes a passing reference to a similar law being overturned in Japan.

The 700 businesses with revenues in excess of $100 million that would have been forced to disclose their annual tax contributions include James Packer's Consolidated Press Holdings and Gina Rinehart's Hancock Prospecting.

Prime Minister Tony Abbott told the Coalition party room in March that the government would exempt private companies and Mr Frydenberg told colleagues there were "real concerns" over personal safety.

Liberal MP Craig Laundy, whose family sold half its pubs empire into a $400 million joint venture pubs and pokies group with Woolworths in 2012, worked hard inside the party room to have the disclosure laws overturned.

TWU national secretary Tony Sheldon said the absence of advice received by the government proved there is no basis for altering the transparency law.

"A Tax Office briefing document recently showed Australia's biggest 900 companies claimed tax deductions and exemptions worth $25 billion last year. Workers meanwhile continue to legitimately pay their taxes and carry the greedy elite," he said.

Shadow assistant treasurer Andrew Leigh said the BRW Rich List proved there was sufficient information already available on the wealth of individuals and companies doing the right thing should have nothing to hide.