The agreement comes just days after struggling St Mirren confirmed their top-flight status for next season with a 1-0 midweek win over Aberdeen.

Mooy, 20, had originally joined the Saints in September last year after leaving Bolton in the previous off-season.

The Sydney-born attacking midfielder has made 18 appearances for St Mirren this term, the majority coming after the turn of the year with that run of form prompting the new deal.

Saints boss Danny Lennon decided earlier this week for a major overhaul of the club's playing squad with 11 players released.