Spain's political parties have made a grab for editorial control of news at the country's public broadcaster, with their representatives granted access to material before it is broadcast.

The political appointees who make up the governing board of broadcaster RTVE shocked staff by voting to give themselves access to scripts and videos due to be used in news programmes.

Wednesday's vote meant all governors would be given passwords allowing them to enter the editorial system and read through scripts or view videos.

Journalists at the broadcaster immediately accused the governors, appointed by political parties and trades unions, of plotting to censor broadcasts before they were aired.

"This opens the way to censorship, political control and other kinds of pressurising," the broadcaster's news journalists' committee said.

It added that governors should have no role in "the way in which news is chosen, gathered, corrected or put together.

"That job falls directly on the news executives, editors and all the professionals involved in the elaboration of news items."

The measure was proposed by governors named by the conservative opposition People's party (PP), and allowed through when socialist party nominees abstained from voting. A representative from the Catalan nationalist Convergence and Union coalition also voted in favour of the change.

The PP has long claimed that senior news executives, in particular director Fran Llorente, were pro-socialist. Llorente told a meeting of RTVE journalists he would not permit political interference in news gathering.

Socialist board members have not explained their decision to abstain. Only the two union representatives voted against the change.

Governors gave themselves full access to the internal news system, known as iNews. Access was previously restricted to the chairman of the board of governors – a position that is currently vacant.

The measure provoked outrage in the press and among political parties not represented on the board.

"They have lost it," said Basque nationalist deputy José Ramón Beloki, who called on the eleven board members to resign.

Cayo Lara, head of the United Left coalition, said: "This is an attack on independence and on intelligence."

Even the political masters of those on the board criticised the measure, which came as the parties prepare for a general election campaign.

"I don't like this, supervision is not a good idea," said the PP's official spokesman, Esteban González Pons.

"This is a mistake," Alfredo Pérez Rubalcaba, socialist party candidate for prime minister in the November election, told the Guardian. "I don't agree with the decision and I hope the board will reconsider it."

In response, the PP-appointed governors called a special board meeting for Friday to strike the measure out.

"We have reconsidered our the decision, which is why we will ask for the measure to be cancelled," a spokesman said.

El País newspaper reported that governors at RTVE earn €120,000 (£105,000) a year and have the right to secretarial support, a personal adviser, chauffeur and official car. Nine are proposed by political parties and two represent the country's biggest trades unions.

In recent years, attempts have been made to reduce the level of political control in RTVE newsrooms. In 2003, a presenter on the main news programme was famously forced to read the contents of a court judgment that condemned it for inaccurate reporting of a general strike.

Mariano Rajoy, the PP leader who is expected to become prime minister in November, welcomed his governors' U-turn.

"They must have thought harder about this decision than the one they made earlier," he said.