Ghana’s parliament has tipped in favour of the main opposition party by one seat, after the defection of four MPs, less than two months before general elections.

Four lawmakers — two from the ruling New Patriotic Party (NPP), one from the main opposition National Democratic Congress (NDC) and one independent — said they would run in the December 7 legislative elections under fresh affiliations.

However, the Ghanaian constitution bars MPs from defecting from the party for which they were elected, to run again for another party or as independent candidates.

Parliamentary speaker Alban Bagbin on Thursday declared that four seats were vacant, with the NDC now holding a slight majority.

“Defection is prohibited because it undermines the trust placed in MPs by their constituents and can lead to instability in parliament,” Bagbin said.

A presidential vote will be held alongside the legislative election, with a fierce battle expected between the NPP and the NDC.

The shift in the balance of power has raised concerns about key bills being passed.

They include on nuclear energy, a World Bank loan agreement and the protection of the environment, which in Ghana is threatened by illegal gold mining.

The NPP has challenged the vacancies and filed a lawsuit with the Supreme Court.

NPP members, led by Alexander Afenyo-Markin, walked out of the parliamentary sitting and vowed to boycott further sessions until the court issues its ruling.

“Going forward, we will not participate in any further parliamentary sittings until these vexed matters are determined by the Supreme Court,” Afenyo-Markin said.

Rasheed Draman, executive director of the African Centre for Parliamentary Affairs, an organisation supporting parliamentary work, said that “both sides must seek compromise and negotiation” to avoid deadlock.

“This situation could paralyse government business, especially with crucial bills on the table,” he told AFP.

Ghana, a country of 33 million people, is often regarded as a rare bastion of democratic stability in a region plagued by coups and conflict.