The United Democratic Movement (UDM) lost its court bid in Port Elizabeth over what it deems the "illegal" removal of its deputy mayor from office, according to EWN.
Mongameli Bobani was removed after a no confidence motion last month.
Judge Dayalin Chetty didn't immediately provide reasons for his decision. The UDM has been ordered to pay the costs of the respondent.
According to EWN, former deputy mayor Mongameli Bobani's legal team had argued for the matter to be heard urgently, saying he was suffering "reputational damage" as a result of his removal through a vote of no confidence at the Nelson Mandela Bay council last month.
The DA argued that Bobani undermined the coalition agreement by voting with the ANC on numerous occasions.
UDM secretary-general Bongani Msomi said the Nelson Mandela Bay Municipality coalition agreement made provision for partners to agree or disagree on matters that are not in line with their party's values.
"There's nothing that could force him to vote with coalition partners if he was not happy with what they were coming up with or if he was not involved."
Msomi added that the UDM remained part of the coalition, which includes the Congress of the People and the African Christian Democratic Party.
"We are committed to the coalition because we've seen that the coalition is above the UDM, it's above the DA. The people you must put first are those in Nelson Mandela Bay."