"We still recognise two traditional sexes and there's nothing in between or beyond ... Any effort to claim otherwise is not allowed."
Tanzania has threatened to ban non-governmental groups that "promote" the rights of lesbian, gay, bisexual, transgender and intersex (LGBTI) people in the first public statement the government has made against the minority group.
Gay sex is illegal in Tanzania and punishable by up to 30 years in prison.
The East African country has a reputation for being more tolerant towards LGBTI people than its neighbour Uganda but recent comments attacking the group have sparked fears and condemnation from activists.
In a statement late on Wednesday, the deputy minister for health, community, development and gender, Hamisi Kigwangala, said the Tanzanian government took traditional values seriously and would "always protect them".
"I cannot deny the presence of LGBTI people in our country and the risk they pose in fuelling the spread of HIV/AIDS but we don't subscribe to the assertion that there's a 'gender continuum'," Kigwangala said.
"We still recognise two traditional sexes and there's nothing in between or beyond ... Any effort to claim otherwise is not allowed.
"Tanzania does not allow activist groups carrying out campaigns that promote homosexuality ... Any attempt to commit unnatural offences is illegal and severely punished by law," he added.
Kigwangala's comments came a month after Dar es Salaam Regional Commissioner Paul Makonda announced a crackdown against gay people in Tanzania's commercial capital.
He said he would use social media platforms such as Facebook, Instagram and Twitter to identify and arrest people suspected of being gay in the port city.
In July, the government announced it would ban imports and sales of lubricants to "curb" the spread of HIV.
Kigwangala said the government, in conjunction with the Tanzania Commission for AIDS, had started to vet gay rights NGOs.
Nurdeen Supa, a gay rights activist with LGBT Voice of Tanzania, an officially registered NGO, expressed concern the government move would further fuel discrimination against LGBTI people.
"They are simply instilling fear in vulnerable people who live their lives without harming anybody," Supa told the Thomson Reuters Foundation.