The Hoops' 3-1 defeat to fellow strugglers Southampton on Saturday left the London club rooted to the foot of the Premier League having still to record a victory.
With their next two matches away at Hughes' former club Manchester United and Sunderland, Parkes, who played at Loftus Road between 1970 and 1979, thinks a change of leadership gives the club the best chance of survival.
"There is only one person who can make the decision and that is Tony Fernandes," he told Radio 5 Live's Sportsweek programme. "They have some tough games coming up and if he carries on backing Mark Hughes and they keep losing it is very difficult to get yourselves out of that position.
"Harry (Redknapp) is hovering in the background and he is a guy who will come in and make a difference straightaway. It is horrible when you see a manager in this position but I would think he would slowly be running out of time and I am not sure how long he can carry on in the job.
"You may have to bite the bullet and say it is time for Mark Hughes to move on. The longer he (Fernandes) leaves it the worse it will be for a new manager coming in and unfortunately that is what they need now, a new direction."