Klopp has struggled to get consistent results from the crop of Liverpool players he inherited from Brendan Rodgers when he replaced the Northern Irishman in October.
But Hansen believes the mixed results say more about the players at Klopp's disposal than the German's managerial ability and has called on the club's American owners to back their manager in the transfer market during the coming off-season.
"These players are not going to win the league, so realistically they probably need five major signings," Hansen said.
"Jurgen Klopp will have taken the job already knowing who he wants to bring in. The owners have brought him in and now they need to back him, but the problem is the money.
"From what I understand Fenway Sports Group have told the manager it is not a bottomless pit. So the problem he might have is that the owners have invested so much already, will they be reluctant to do it again? They have spent a lot - £20m on Lazar Markovic, and then he was sent out on loan.
"You could say they need to spend £100m, but where does that get you in today’s market? If they are going to have a real go it needs to be more like £200m – but you can't just snap your fingers and solve the problem."
Hansen believes a new goalkeeper and at least two new centre-backs should be Klopp's priority.
"The problem with [Liverpool goalkeeper] Simon Mignolet is he'll go on a good run and then a bad run, but the question is whether there is anyone out there who is better," he said.
"Do you give him more time? If you look at someone like David de Gea, when he was first at Manchester United he was called the worst goalkeeper in the world. Now he's being called the best in the world.
"The manager will have to be looking at two goalkeepers and a centre-back. But like with the goalkeeper situation I can't think of too many decent centre-backs out there.
"You need a centre-back partnership to be successful and Liverpool have not had one for a number of years. I look at Wes Morgan and Robert Huth at Leicester and how successful they have been. That’s what Liverpool miss."