There are plenty of questions after an Australian naval ship accidentally blocked internet and radio services across parts of the country.

It's understood the radar of the HMAS Canberra accidentally interfered with one of the shared spectrum bands that anyone can use free of charge.

Intelligence expert Paul Buchanan saysoperational security was lacking.

He wants to know why the Canberra was on a commercial band, given it's the most important ship in the Australian navy

LISTEN ABOVE