Ikponwosa Ero said that the situation "constitutes an emergency, a crisis disturbing in its proportions".
Her call came after two men received a 17-year jail term for murdering a 21-year-old woman with albinism.
Ms Ero said Malawi police have recorded 65 attacks, abductions and murders of albinos since the end of 2014.
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Tanzania's albino community: 'Killed like animals'
Albinos were targeted because of beliefs that their body parts "can increase wealth, make businesses prosper or facilitate employment", said Ms Ero, the UN human rights council's expert on albinism.
"Even in death, they do not rest in peace as their remains are robbed from graveyards," she added.
Ms Ero, herself an albino, said there are economic motivations.
"Malawi is one of the world's poorest countries and the sale of body parts of persons with albinism is believed to be very lucrative."
People with albinism, who lack pigment in their skin and appear pale, are regularly killed in several African countries including Malawi, Mozambique and Tanzania.
Malawi's estimated 10,000 albinos face "extinction" if they continue to be murdered for their body parts for use in witchcraft, a UN expert has warned.