Former coach John Aloisi says Melbourne City's A-League season will soon be over if the club can't overhaul their inept defence.

City were belted 5-1 by Wellington Phoenix on Sunday, piling pressure on beleaguered coach John van't Schip to turn around a string of poor A-League performances.

John Aloisi is the only person other than John van't Schip to have coached Melbourne City. Credit:Getty Images

Van't Schip's side are on track to leak the most goals in A-League history and have just one win in eight matches.

It's a stress familiar to one-time Melbourne Heart boss Aloisi, who led the side before it was bought and rebranded by Manchester City earlier this year.