The two main opposition parties in Hungary have walked out of a parliamentary debate in protest at what they say are government attempts to limit the freedom of the public media.

The opposition Socialists and Free Democrats are trying to block a government proposal to alter the make-up of the regulatory bodies for Hungarian Radio, Duna Television and the MTI news agency.

They say a plan to add extra members to the bodies will give the government permanent control of the three outlets.

The Socialists and Free Democrats lost power to a centre- right alliance in Hungary in May.

The government and opposition have recently clashed over a number of constitutional and procedural issues.