Two members out of Italian public broadcaster Rai's five-member board have resigned, throwing the TV platform into a new state of disarray.

The two members who stepped down on Wednesday are Carmine Donzelli, a publisher, and Luigi Zanda, a lawyer. They were the only two representatives of the centre-left on the board, which is otherwise made up of allies of Silvio Berlusconi's ruling centre-right coalition.

Donzelli and Zanda cited a "lack of pluralism" as the reason for their resignation. "The behaviour of the actual managment risks compromising the strength of Rai, including its production and economic continuity.

"This crisis regards a lack of guarantee of pluralism and freedom of information," they said, pointing to Michele Santoro and Enzo Biagi, two leading RAI presenters whose contracts were not renewed after Silvio Berlusconi publicly criticised them last February for having made a "criminal" use of state-run television.

Santoro, Biagi and satirical comic Daniele Luttazzi were all critical of the premier during the run-up to the May 2001 national elections. Last February, when Berlusconi was asked whether his comments meant the three should lose their jobs, he said, "If they change, I have nothing against them. But since they won't'"

His comments provoked criticism even from some of his staunchest defenders.

In recent months, RAI has come under increasing pressure to defend its decision not to renew Santoro and Biagi's prime-time contracts on its leading channels and its failure to maintain even promises of late night slots on the left-leaning RAI3.

In their letter of resignation, Donzelli and Zanda criticised equally the poor quality of Rai programmes as well as the "badly-handled appointments of new programming and TV drama directors."

New appointments are said to have been delayed amid internal and political in-fighting.

"In the meantime, tens of debatable appointments continue to fuel the suspicion of a conflict of interest," they said of Rai, whose board of directors was appointed by the government of Berlusconi who also owns Rai's only rival, Mediaset.

The board of Rai's film unit, Rai Cinema, is also up for renewal at the end of November.