Venezuela’s opposition leaders have accused the government of President Hugo Chávez of launching a campaign of persecution aimed at stripping them of power since they won key posts in regional elections last year.

Many of the leftwing leader’s most high-profile opponents are either being investigated for corruption or subjected to new laws that restrict the exercise of their powers.

Antonio Ledezma, an anti-Chávez leader who was elected as mayor of Caracas last year, called his subordination to a new official to be handpicked by the president a “coup” against the constitution. Legislators loyal to the government passed a law last week creating a new official with administrative and budgetary control over Venezuela’s capital.

Analysts say Mr Chávez is using his control over state institutions to centralise power and emasculate his political opponents at a time when plunging oil revenues are pressing the government to cut spending as Venezuela slides into recession.

Manuel Rosales, the opposition candidate in the 2006 presidential elections who is facing corruption allegations, has gone into hiding, saying he would not get a fair trial. Meanwhile, General Raúl Baduel, an ally-turned critic of Mr Chávez, was arrested at gunpoint last week and imprisoned over corruption charges.

Government supporters accuse the opposition of hypocrisy, arguing that they regularly denounce corruption but complain when it is investigated. They say Mr Rosales has not been arrested, while Gen Baduel had missed seven summonses to testify in court over $19m (€14.5m, £13m) of public funds said to have vanished while he was defence minister.

Marino Alvarado, director of the Caracas-based human rights group Provea, said the government was not being even-handed in fighting corruption. “They don’t seem to be investigating any of Chávez’s followers,” he said. “The fight against corruption is politicised.”

Critics also say the judiciary lacks independence, and question the fairness of trials of opposition figures.

Gregory Wilpert, a political scientist supportive of Mr Chávez’s “Bolivarian revolution”, described the president’s attempts to centralise power as “disturbing”, and said a law stripping opposition governors and mayors of control of ports, airports and highways seemed to be “unconstitutional”.