Optus owner Singtel has received an amended tax assessment from the Australian Tax Office demanding payment of A$326 million – and at this stage is preparing to fight the matter.

The amount sought by the tax man appears to have nothing to do with ATO and the Government’s pursuit of ITC companies evading Australia taxation by using low-tax countries – of which Singapore is certainly one.

In fact it derives from a long battle between Singtel and the ATO that began some 15 years ago over Singtel’s acquisition of what was then known as Cable and Wireless Optus.

In a release to the Singapore exchange this week, Singtel said its Australian subsidiary had received the amended assessments, comprising primary tax of A$268 million and interest of A$58 million.

It said that, in accordance with ATO practices, it will pay a minimum amount of 50pc of the assessed primary tax by December 28 – but made it plain a good old stoush is ahead. The subsidiary “is a significant taxpayer in Australia and does not agree with the ATO’s amended assessments,” said Singtel. “It has received advice from external experts in relation to the matter and intends to vigorously defend its position.”