Tanzanian police have arrested a woman who appeared in a video showing a kiss between two women that went viral on social media.

Ahmed Msangi, police chief in Tanzania's Mwanza region, confirmed the woman had been held for breaking laws banning homosexuality.

He said "it is just a matter of time" before law enforcement officers found and arrested the other woman and other people seen in the video.

"The plan is to eliminate the entire chain of people involved or supporting homosexuality for the betterment of the generations," he said.

Homosexual relations are illegal in Tanzania and the law prescribes jail terms of up to life.

The East African nation has launched a countrywide crackdown against people accused of promoting homosexuality.

Authorities have threatened to deregister NGOs accused of supporting gay people.