Andersen, who molested hundreds of young boys across southern Norway between 1976 and his arrest in 2008, claims that he has responded well to therapy and is now no longer a danger.
"He has served his sentence, and must have the opportunity to rejoin society," Thore Langefeldt at the Central Institute for Clinical Sexology and Therapy, told VG newspaper. "He has progressed well and I have no problems in agreeing with Dr Randi Rosenqvist's conclusion [that he be released].
Andersen, a kroner millionaire who ran a well-known car garage in Bergen and was active in motor sports, was dubbed "The Pocket Man" during the 30 years he managed to evade the police for his unchanging modus operandi.
He would trick young boys into touching his genitals by asking them, for example, to look for a key in his pocket after he had cut a hole in the lining, or to adjust a bandage.
More seriously, he on several occasions forced young boys to perform oral sex on them.
The police registered about 160 cases which had his unmistakeable stamp, starting with an assault in Åsane, Bergen, in 1976. He was indicted and charged for 60 of these cases, and admitted to 20.
The final recorded incident took place in Svinesund, Sweden, in October 2007.
It was not until 2003, however that police realised that disparate cases which took place in towns across southern Norway showed the signs of being the work of one man.
Andersen was finally arrested in 2008, and in 2010 was sentenced to preventive detention with a term of 9 years, with the possibility of extension if he was still deemed a danger to society.
He was also ordered to pay between NOK 20,000 and NOK 125,000 to each of his victims, a total of NOK 2,525,000.
Norway's VG newspaper controversially named Andersen, publishing his photo across its front page, flaunting a convention in which Norwegian papers rarely name those accused of crimes.