A court in Zimbabwe has thrown out a bid by Locadia Tembo to block Prime Minister Morgan Tsvangirai’s wedding on Saturday to his fiancée, Elizabeth Macheka.

Locadia Tembo had argued that the wedding could not take place because she was Morgan Tsvangirai’s wife under customary law.

But High Court Judge Antonia Guvava ruled such marriages were not valid.

President Robert Mugabe, who is in a fractious coalition with Morgan Tsvangirai, is due to attend the wedding.

The wedding is expected to take place in an upmarket area north of the capital, Harare.

Robert Mugabe is billed to host a post-wedding banquet for other heads of state who will be there, he says.

Locadia Tembo had argued that Morgan Tsvangirai’s wedding could not take place because she was his wife under customary law

Morgan Tsvangirai, 59, and Robert Mugabe – the leaders of the Movement for Democratic Change (MDC) and Zanu-PF respectively – are expected to run against each other in presidential elections, due next year.

The case brought by Locadia Tembo, a 39-year-old commodity trader and sister of an MP from Zanu-PF, was heard in chambers in the High Court in Harare.

The judge ruled that marriages under customary law were not valid, expect for certain purposes such as the distribution of matrimonial property.

He also said the case should have been dealt with by a marriage officer at a magistrate’s court.

Locadia Tembo’s lawyer, Everson Samkange, said he would now lodge a further objection to the marriage with the magistrate’s court, which could lead to a commission of inquiry if the case goes ahead.

But Morgan Tsvangirai’s lawyer, Innocent Chagonda, said he welcomed the fact that “legal impediments” had been removed ahead of the wedding.

“There was no basis upon which [Locadia Tembo] could have interdicted the prime minister from getting married,” he said.

“An unregistered customary law marriage is not a valid marriage at all. It is valid for only certain purposes which have nothing to do with what we have been talking about.”

Locadia Tembo, a businesswoman, has been demanding $15,000 a month in maintenance expenses from the prime minister.

Morgan Tsvangirai’s 35-year-old bride is the daughter of Zanu-PF loyalist and former Chitungwiza mayor, Joseph Macheka.

In November, reports said that Locadia Tembo and Morgan Tsvangirai held a traditional wedding and Tsvangirai had paid a bride price of several hundred thousand dollars.

Shortly thereafter, Morgan Tsvangirai said their relationship had been “irretrievably damaged” after it was “hijacked” by his opponents, including state security agents.

Morgan Tsvangirai’s first wife, Susan, died in a car crash soon after he became prime minister in 2009.