Czech lawmakers have narrowly voted to charge outgoing Czech President Vaclav Klaus with treason.

The upper house voted to refer the president to the constitutional court to rule on whether he had violated the constitution with a New Year amnesty, the BBC reported.

The wide-ranging measures were controversial as they resulted in multiple high-profile corruption cases being suspended. Klaus's term as president of the country is due to end on Thursday.

Thirty-eight senators in the 81-seat house, controlled by the left-wing opposition, voted to file charges at the constitutional court, with 30 voting against. Only the Senate has such power in the Czech legal system.

The worst punishment he faces is the loss of his presidential job, a role the 71-year-old must relinquish later this week having served two terms in office.

The president's New Year measures included an amnesty for many prisoners.

It was not, however, the decision to free some 7,000 prisoners serving sentences of up to a year or cancel all suspended sentences, but rather the halting of the prosecution of cases that had dragged on for more than eight years that caused widespread public anger.

In one fell swoop, a dozen high-profile corruption cases - cases that involve millions of dollars in asset-stripping, bribes and fraud - were thrown out.

The halted prosecutions included that of prominent businessman Tomas Pitr for alleged tax fraud and that of former football association chief Frantisek Chvalovsky for embezzlement.

The senators also accuse Klaus of flouting the constitution by refusing to ratify European treaties, and for refusing to rule on the appointment of judges despite being ordered by courts to do so.