Not necessarily "banned," but certainly considered unethical by the the Norwegian Psychiatric Association and is frowned upon in the industry.
"In 2000, the General Assembly of the Norwegian Psychiatric Association overwhelmingly voted for the following position statement on sexual orientation change therapy:
'Homosexuality is no disorder or illness, and can therefore not be subject to treatment. A ‘treatment’ with the only aim of changing sexual orientation from homosexual to heterosexual must be regarded as ethical malpractice, and has no place in the health system.'"
Norway intends to officially ban conversion therapy in 2022.