The National Democratic Congress (NDC) said it was alarmed at the use of armed policemen to arrest one of the union leaders of the Bank of Ghana, Mr Benjamin Duffuor.
It said there were also several policemen wielding AK 47 guns around and he was subsequently detained for more than seven hours.
A statement signed by Mr Elvis Afriyie-Ankrah, Deputy General Secretary, Operations, of NDC, said it smacked of an attempt to intimidate unionized workers, stifle free expression, and introduce a "culture of silence and fear in the Ghanaian body politic".
The NDC also stressed that, it was appalled at the high handedness and the illegal and unconstitutional manner in which the two union leaders of the senior staff of the bank were served with their letters of dismissal without citing any concrete reasons.
The statement said the harassment, heckling and punching of other innocent staff who were demanding the legal basis of such an action was an affront to the human rights and dignity of these staff.
"The NDC condemns in no uncertain terms these acts of brigandage and urges all right thinking Ghanaians, civil society, the clergy, the media and especially the Labour Commission to intervene immediately to restore sanity and confidence in the sanctity of the rule of law, equal rights and the rights of organized labour to express themselves freely and lawfully without any fear of intimidation or victimization," it said.