THE BEDOUIN tribesmen who roam the semi-arid Negev region of southern Israel stand to lose 20,000 acres of ther land under a bill introduced in parliament. The land is needed for the new military air bases that the United States and Israel are to build to replace the Sinai ones which Israel must hand back to Egypt in 2 1/2 years' time. Because of this urgency, the proposed law provides that the tribesmen should have no recourse to litigation.

The Israeli government's traditionally good relations with its Bedouin citizens have soured in the past three years. The Bedouin will have nothing to do with the government's efforts to build them permanent villages, saying: "The desert is our dwelling and the desert has no borders."

Relations deteriorated badly when the Bedouin ignored regulations limiting the size of thir flocks. Since their lands are parched for half the year, the Bedouin and their herds head north in the summer months, invading cultivated fields and orchards. The agriculture ministry set up a security force, known as the Green Rangers, to hold back the famished goats and sheep. There have been frequent clashes and the flocks have been impounded.

The Bedouin sheikhs were not therefore inclined to look favorably on the government's efforts to reach a quick land settlement. The offer was a quarter-acre of irrigated land for every 25 acres of desert, plus cash compensation for buildings or water holes. Better terms were demanded -- otherwise, long court action. The government countered with the legislation that would deny the Bedouin landowners the right to go to court to fight the expropriations; all they could do is to dispute the amount of compensation before government committees.

Many members of Israel's parliament were unhappy over a bill that would deny Israeli citizens the right to litigation on a fundamental matter. The issue has been milked for its considerable political potential. But the Bedouin chiefs themselves are mainly concerned to get the best deal they can for their land. If the new hill is scrapped, the government and the Bedouin may yet be able to strike a bargain.