The 28-year-old shot-stopper, who was called into a Socceroos squad in mid-2015, is a free agent after leaving Leyton Orient following their relegation from League Two.

Poland-born Hobart-raised Cisak spent two-and-a-half years with Orient but fell out of favour in the second half of the 2016-17 season.

Cisak came through the ranks at Leicester City and spent time on loan at Portsmouth in 2012.

Cisak against Liverpool in the FA Cup in 2012

Portsmouth signed goalkeeper Luke McGee from Tottenham on a permanent deal on Wednesday, but only have one other goalkeeper, 19-year-old Alex Bass, on their books currently.

Veteran custodian David Forde has returned to Millwall after a loan, while back-up keeper Liam O'Brien moved to Coventry City.

Portsmouth finished as League Two champions in 2016-17, earning promotion to England's third tier.