"The (EU) Presidency regrets that politically motivated abuse persists in the country," Sweden said in a statement.
"The decision taken yesterday, together with reports during the last few months of unsubstantiated legal measures taken against several MDC (Movement for Democratic Change) members of parliament, is cause for serious concern," the statement continued.
Zimbabwean magistrate Lucy Mungwari earlier ordered ministerial nominee Roy Bennett, a close aide to Tsvangirai, back to jail to face terrorism charges next week.
She announced Bennett’s trial will start on Monday in the high court of the eastern town of Mutare and told the court: "The accused person shall be committed to prison."
The move "indicates a lack of commitment to the letter and spirit of the Global Political Agreement (GPA)," which allowed for the formation of Zimbabwe’s unity government including both Tsvangirai and President Robert Mugabe.
The EU presidency, held by Sweden till the end of the year, called for "an end to politically motivated persecution in Zimbabwe", while stressing that the European Union "stands ready to assist the inclusive government in implementing the much-needed reforms… in the areas of democracy, respect for human rights and restoration of the rule of law."
The EU statement recalled that the parties to the GPA "agreed last year to build a society free of violence, fear, intimidation and hatred. This commitment should be honoured without delay."
Bennett, the Movement for Democratic Change treasurer, is a white coffee grower whose property was expropriated under the country’s controversial land reform laws.