The nobles, with some support from independents in the parliament, could muster just ten votes to the 14 in support of the prime minister.
Mr Pohiva, the first commoner elected to lead the country, has been prime minister for just over two years.
The country's nobles have been leading a campaign to remove him, but Mr Pohiva said their complaints had no basis.
Meanwhile it has been reported that Lord Ma'afu, who is a member of Mr Pohiva's government, has been abandoned by the country's other nobles.
