"Many emails from mothers and fathers of daughters receiving their army cadet slouch hat," Mr Hancock said. "And all these kids proudly wearing their uniform and hat represent so much of what Australia stands for."

The family-owned, Australian hat manufacturer is the official provider of hats for the Australian Army. Mr Joyce, who has been treated for skin cancer three times, is regularly spotted wearing a wide-brimmed version, even indoors during his time on the hustings through last year's New England byelection.

Prime Minister Malcolm Turnbull and Deputy Prime Minister Barnaby Joyce celebrate his byelection win in December last year. Credit:Alex Ellinghausen

With this new attack on Mr Joyce, who is expecting a child with his former staffer following an affair, Mr Hancock wants to ''highlight the politicisation of Australian symbols by someone who many people have suggested does not represent such ideals. Barnaby wore the hat indoors, at inside formal occasions and has been associated with the hat to the extent its a reference to him in newspapers," he said.

"The Akubra hat has been worn by many great Australians, who first showed the world the loyalty, bravery and selflessness that Australians became known for. It carries symbolic reference to ideals that Barnaby Joyce has not, through his repeated actions and judgments, and generally putting himself first.