Revealing the secret identifies behind shell companies and opaque trusts is the "new frontier" in fighting tax evasion, says the OECD's head of tax Pascal Saint-Amans.

In an exclusive interview with Fairfax Media, Mr Saint-Amans also spoke about the Turnbull government's tougher domestic laws aimed at cracking down on multinational tax avoidance, which, according to the tax man, are expected to lead to $4 billon in new tax bills issued against the nation's biggest companies.

But the Paris-based Mr Saint Amans, who is the public face of the OECD/G20 crackdown on multinationals, said, while Australian laws appeared to be in line with the global plan to fight profit-shifting, it was possible tax authorities in other nations such as the United States could dispute Australia's right to tax.

Since the release of the Panama Papers last year, countries including Australia have been considering beneficial ownership reforms, which would reveal the secret people behind shell companies.