HARARE, Zimbabwe (CNN) -- A Zimbabwean opposition party member was arrested just before he was to become the troubled country's deputy agriculture minister, the opposition Movement for Democratic change said.
Roy Bennett, left, pictured with MDC leader Morgan Tzvangirai, is also the party's treasurer.
Roy Bennett, who is also the party's treasurer, was pulled from an aircraft Friday at the airport in the capital, Harare, as he was about to fly to South Africa, the MDC said.
Zimbabwean police spokesman Wayne Bvudzijena told CNN he was still trying to confirm Bennett's arrest.
The MDC said in a statement Bennett was being charged with attempting to leave the country illegally.
"However, they keep backtracking and are incoherently inconsistent on what they intend to do and charge him with," the party said.
Hundreds of party members and supporters have surrounded the Mutare police station, where Bennett was being held, the party said. Three lawyers were also in attendance to represent him, according to the statement.
The incident happened the same day that all MDC ministers in the new unity government took their oaths of office. Watch how the arrest may threaten unity »
The swearing-in eventually took place but was delayed, the MDC said, because President Robert Mugabe and his ZANU-PF party wanted to appoint more ministers than they were allowed in the new government.
Under the power-sharing deal signed in September, the ruling ZANU-PF party gets 17 cabinet posts and the MDC gets 13.
Mugabe brought a "bloated" list of 22 Cabinet ministers to the swearing-in ceremony, five more than permitted under the agreement, the MDC said.
Proceedings were delayed after MDC leadership insisted Mugabe stick to the 17 agreed Cabinet posts, the opposition party said.
The five ZANU-PF members had to leave the podium after MDC ministers vowed that they would not participate in the swearing in ceremony.
Tendai Biti, MDC secretary-general who is now Zimbabwe's finance minister, said the MDC ministers would not leave their seats "unless you hit us or you send a crane." Watch Biti talk about the challenges he is facing »
The stalemate lasted for more than an hour, but 17 ministers eventually were sworn in.
On Thursday MDC leader Morgan Tsvangirai spent his first full day as prime minister and called it "hectic."
Tsvangirai met union leaders and political detainees at a maximum-security prison, and planned to talk later to donors, he told journalists.
He was sworn in as head of government Wednesday under a power-sharing agreement with Mugabe. Watch Tsvangirai take the oath of office »
Tsvangirai met the media in an office with new furniture and freshly painted walls, while painters and carpenters down the hall were still busy renovating the offices of his deputy prime ministers.
The unity government is the result of a power-sharing agreement reached in September between Tsvangirai and Mugabe after months of squabbling about the results of elections earlier in the year.
A cholera epidemic has claimed close to 4,000 lives and infected about 65,000 people since August, aggravated by a lack of water-treatment chemicals and a problem with waste disposal in much of the country.
The United Nations says more than 5 million people are in need of food aid, in a country that has shortages of all essentials, including fuel, electricity and cash.