Redknapp’s men are back in the Premier League after winning the Championship play-off final last spring but lost 1-0 to Hull in their season-opener at Loftus Road.
Steven Caulker, Jordon Mutch, Rio Ferdinand and loanee Mauricio Isla have arrived this summer but Redknapp thinks the squad is still a little thin.
And he hopes that further additions will be announced shortly, with more loan signings a distinct possibility.
"We need to get a couple more in, we're short in some areas," said Redknapp.
"I've got three central midfield players - Joey Barton, Alejandro Faurlin and Karl Henry - when you need six midfield players really, at this level.
"So we're looking to get one or two midfielders in and maybe a front man as well, because we need a bit of cover there. You need four strikers, in an ideal world.
"If you look at the whole squad, with everyone fit we've got 18 or 19 outfield players, and that includes one or two lads who couldn't get in the squad last year.
"We'll probably use the loan system again. Maybe we'll buy one and loan a couple."
Forward Loic Remy played against Hull after a proposed move to Liverpool fell through but his future remains somewhat uncertain.
"He's got a buy-out clause which is a problem because, if someone comes in and offers the money, you lose him," said Redknapp.
"If he goes you're looking for two strikers, which isn't easy to find but, if he's going to leave QPR, it's got to be to a big club - a top-seven club, I would think.
"He didn't want to go back to Newcastle which is a massive club so, unless it's a club in the top seven, I don't think he'll go."