Many former detainees have said they received no vocational training.
Zakir said the facilities were meant to improve job skills and Mandarin abilities among minorities with "a limited command of the country's common language and a limited sense and knowledge of the law".
China's detention camps are "training" centres that have made lives more "colourful" for Muslim minorities by saving them from extremist behaviour, a senior official said on Tuesday, in a robust defence of the policy amid growing global criticism. "The goal is to fundamentally eliminate the environment and soil that breeds terrorism and religious extremism, and eliminate the terrorism activities before they take place".
China rejects the accusations of mistreatment and initially denied the existence of the facilities, but has changed its stance as satellite imagery and released government documents made that position impossible to maintain. Zakir's interview represents one of the most detailed accounts of China's defence of the centres and what goes on inside them. Skills training included food processing, assembling electronic products, hairdressing, clothes making and e-commerce.
Zakir's comments come a week after Xinjiang inserted into its anti-extremism regulations new clauses that prescribe the use of "vocational training centres" to "educate and transform" people influenced by "extremism".
The official did not say how many people were being held in the centres.
"The Communist party is clearly on the defensive, seeking to deflect worldwide criticism of its radical new policies in Xinjiang and justify them retrospectively", said James Leopald, a scholar focusing on Chinese ethnic policies at La Trobe University in Melbourne.
Relatives living overseas have also said family members in Xinjiang have cut contact with them due to fears communicating with people overseas could incur punishment from authorities.
Human rights groups and Uighur advocacy organisations outside China claim the centres - which first appeared in 2017 - are arbitrarily detaining innocent people, mainly men, and subjecting them to political indoctrination.
The governor of Xinjiang described a life in the centres that is in stark contrast to the accounts given by witnesses of poor nutrition and constant surveillance.
Zakir said the training institutions "care about the mental health of students" and provide counselling services. One former detainee told the Guardian he had attempted to kill himself. He said the cafeterias in the camps prepare "nutritious diets" and that all dormitories were equipped with radios, televisions, and air conditioning.
"Various activities such as contests on speech, writing, dancing, singing and sports are organised", Mr Zakir is reported to have said.
"Many trainees have said that they were previously affected by extremist thought and had never participated in such kinds of art and sports activities, and now they have realised that life can be so colourful", he said. Zakir said some trainees were "expected to complete their courses successfully by the end of this year".