Police in Tanzania say they have arrested four people over the kidnapping of an albino girl in the north of the country, where many are killed and their body parts sold as lucky charms.

Four-year-old Pendo Emmanuelle Nundi was snatched on Saturday from her home in the Mwanza region by attackers armed with machetes, regional police chief Valentino Mlowola told state television.

"We have arrested four people, including the girl's father. We are still in the process of interrogating them so we can find out where the girl is - if she is still alive," the official said, adding the attackers may have been tipped off by neighbours.

At least 74 albinos have been murdered in the east African country since 2000, according to United Nations experts. After a spike in killings in 2009, the government placed youngsters in children's homes in a desperate effort to defend them.

A hereditary genetic condition which causes a total absence of pigmentation in the skin, hair and eyes, albinism affects one Tanzanian in 1,400, often as a result of inbreeding, experts say. In the West, it affects just one person in 20,000.

In August a UN rights expert warned that attacks against albinos were on the rise because Tanzania's October 2015 presidential election was on the horizon, encouraging political campaigners to turn to influential sorcerers for support.

Albino body parts sell for around $US600 ($A650) in Tanzania, with an entire corpse fetching $US75,000.

AFP