Central Coast Mariners coach Phil Moss has thrown down the gauntlet to Mitchell Duke, challenging the striker to recapture the form that earned him an international call-up last season.

The 23-year old scored six goals in his first full campaign and won plaudits for his explosive style, with many tipping him to be one of the A-League's next big exports.

Mitchell Duke has had a tough season with the Mariners. Credit:Getty Images

While he has had more game time this season, the goals have dried up and he has lost his place in the starting side, despite the departures of Daniel McBreen and Michael McGlinchey and injuries to Adam Kwasnik and Marcos Flores.

Moss still believes in the striker - who is likely to start on the bench for the Mariners against Sydney FC at Bluetongue Stadium on Saturday night - but feels he needs to focus on his situation rather than a foreign transfer.