The head of Wesfarmers says his main competitive threat comes from Amazon, the US-based retail website, rather than rival grocery Woolworths. He would like to keep his physical stores open ‘‘24/7’’ to compete properly with the internet, he says.

Wesfarmers chief executive Richard Goyder also says Australia’s corporate tax rate ought to drop significantly to give local companies a chance to compete with corporations that use global tax havens to avoid paying tax.

Post mortem: Wesfarmers sees Amazon as a bigger threat than its local retail rivals.

Speaking at the National Press Club on Tuesday, Mr Goyder said Wesfarmers – the owner of Australia’s second-largest supermarket chain, Coles – no longer thought its biggest competitor was Woolworths or Big W or ‘‘one of the other physical competitors’’.

Market definitions needed to be challenged by the regulator because they were being challenged by ‘‘all markets’’ at the moment, he said.