Disarmament campaigners have launched a legal challenge to Israel's secretive nuclear agency, demanding that it be given democratic authorisation.

The Israeli Disarmament Movement has written to Prime Minister Binyamin Netanyahu requesting that he legislate for the existence of the Israeli Atomic Energy Commission. Set up behind the scenes in 1952 to manage Israel's nuclear activities, the commission has never been affirmed in law, campaigners say.

The commission runs two research reactors in Soreq and in the Negev desert, and says it helps develop nuclear energy for civil purposes. But it is widely suspected of also being involved in nuclear weapons development.

Israel maintains a deliberate policy of "nuclear ambiguity" and has never confirmed that it has nuclear weapons. But US experts have estimated it could have as many as 80 nuclear warheads.

The Israeli Disarmament Movement's initiative has been backed by a former Israeli politician and peace campaigner, Mossi Raz; Professor Avner Cohen, an expert on Israeli nuclear policy from the Middlebury Institute of International Studies in Monterey, California; and the Israeli lawyer, Itai Mack.

Netanyahu and his energy minister, Water Yuval Steinitz, have been given 90 days to announce that work has begun on legislation for the atomic commission. If there is no response, the campaigners are threatening to launch a long legal battle that could end up in Israel's supreme court.

The commission was created by a secret administrative order and has been maintained by secret government decisions, they say. The failure to give it any legal backing has created "an extraordinary and problematic lacuna in terms of Israeli democracy", they argue.

Mossi Raz, a member of the Israeli parliament, the Knesset, from 2000 to 2003, said: "We are of the opinion that the current situation does continuing damage to the basic principles of a democratic regime, as it gives almost unlimited authority to the state's executive branch."

Sharon Dolev, director of the Israeli Disarmament Movement, pointed out that the commission's activities had consequences for public safety, health and the environment. "These are issues that concern each and every one of us," she said. "Yet we know nothing of those activities and there is no supervision over them."

Nadav Shaltiel, a member of the movement, added: "Beyond the fundamental damage to democracy, the current situation creates a very problematic conflict of interests. The commission is an executive body and at the same time a supervisory body."

The lawyer, Itai Mack. argued that giving the commission legal authority would not necessarily mean an end to the policy of nuclear ambiguity. "But we can at least hope for legislation that establishes its authority, its organisational structure and supervision over its activities," he said.

Campaigners are concerned that their move might not be reported in Israel due to state censorship. The Israeli government did not respond to requests to comment on Friday.