SYDNEY: Australia's two-game series against Women's World Cup champion the United States is in doubt after the players went on strike ahead of the last practice.

Football Federation Australia said it condemned the Professional Footballers Australia (PFA)’s decision to take industrial action without notice, forcing national women's coach, Alen Stajcic, to cancel practice on Tuesday and jeopardize the matches scheduled for September 17 and 20 in the US.

The PFA instructed the players to boycott practice, hours before negotiations on a Collective Bargaining Agreement were set to restart.

The PFA is seeking an increase in the salary cap at each of the 10 A-League clubs, an increase in payments for international matches, and increases in spending on wages, air travel, accommodation, and benefits for the Matildas, the national women's team.