A financial scandal is threatening to unseat Africa's only female head of state, the president of the Indian Ocean nation of Mauritius.

President Ameenah Gurib-Fakim, whose role is mostly ceremonial, faces allegations that she used a credit card provided by a non-governmental group to buy luxury goods.

Gurib-Fakim said this week that she "inadvertently" used the credit card from the London-based Planet Earth Institute for "out-of-pocket" expenses of about $27,000, and that she had paid back the money.

The president says she is the victim of a smear campaign and won't resign, contradicting an earlier comment by Prime Minister Pravind Jugnauth that she would quit after Mauritius celebrated its 50th anniversary of independence from Britain last Monday.

Gurib-Fakim, 58, was appointed as president in 2015.