Speaking to Sky Sports News, the 33-year-old criticised Magath's style of management, believing it to have contributed towards the club's relegation last season, and he has tipped them to continue on a downward spiral.
Fulham responded, telling Sky Sports News they are "baffled" by Hangeland's comments and labelling them "totally inaccurate", before insisting Magath is the right man to restore their place in the top flight.
But Hangeland said: "He is very difficult to work with. He has a reputation of being a very strict manager, which he is.
"His main tool is to try and mentally and physically batter his players and then hopefully get some results out of that. Is that a right fit for English football? I don’t think so personally.
"Rather than help us try and avoid relegation, he made things worse and harder for us. I hope I’m wrong because I really love the club but, in a word, no - I don’t think he is the right man.
“I think things will get worse before they get better and I really think that what’s happening now at the top of Fulham is very disconnected, and very far from the Fulham that I know and from the Fulham fans.”
Hangeland revealed last month that Fulham informed him about the cancellation of his contract via email, and described his unhappiness at how the club brought to an end his six-and-a-half-year stay at Craven Cottage.
“After relegation the manager asked me if I wanted to play in the Championship with Fulham," the Norwegian said.
“I told him 'I’m going to be really honest, this club has been on the decline for a few years now and I need to know that we are going to move in the right direction'.
“We left it there and two weeks later they called my agent and told me they wanted to do a press release saying that I am no longer with Fulham. I said 'I don’t agree with that so I can’t be part of that'.
“Then the next day, I received an email from them cancelling my contract. I don't know whether to laugh or cry when I think about it really. After six and a half years, I thought that was harsh.”
Fulham insisted at the time that they acted properly regarding Hangeland's release, and following the player's latest criticism, the club said: "We are bemused by Brede’s comments, which we feel are totally inaccurate.
"Sixteen months ago, Brede signed a multi-million-pound contract at the club and expressed his delight at staying, and at no point during these negotiations did he mention he felt the club was not moving in the right direction.
"Felix Magath is fully focused on pre-season preparations in Scotland and the club is confident he is the right manager to make sure Fulham moves forward.
"Regardless of his comments, Fulham hold Brede in very high regard and wish him well for the future."