Representatives from some 200 American Indian tribes began gathering here yesterday in an unprecented effort to wage a unified battle against what the Indian nations see as a pervasive national effort to dismantle their tribal rights.

The tribal leaders say they hope to develop during three days of strategy meetings a response to what is bitterly referred to here as "the backlash" - the legislation pending in state capitals and Congress and efforts by governmental organizations to curb some of the sovereignity of the tribes.

Veronica Murdock, president of the National Congress of American Indians, called it "the most desperate fight for survival . . . to help defeat the backlash and change the public attitude that supports outrageous legislation."

Her remarks abouts this newest threat to American Indians followed a solemn presentation by a Navajo Veterans of foreign Wars Post of the flag of the nation that conquered these native Americans.The gathering was called by the Navajo Tribal Council, which has its headquarters here and which provided $100,000 for the conference after declaring last fall that a "state of emergency" exists for Indians today.

The nation has somewhat fewer than 1 million Indians, and the Navajos account for probably half of them. Thus the role staked out by the Navajos is deemed particularly significant.

Tribal leaders from almost half the nation's 493 recognized tribes are expected to attend and grope for unity on political and economic issues facing them. Representatives from tribes in Maine and Hawaii and almost everyplace in between are expected to attend.

"We're here because time is running out and because our survival is at stake," says Peter MacDonald chairman of the Navajo Tribal Council. MacDonald and Murdock are both critical of the Carter administration, seeing in it a greater concern for human rights in distant lands that for the original Americans.

"We are under attack on several fronts," says MacDonald, "the courts, the media, legislatures, taxation, treaty rights, sovereignty, federal funds, water rights, land claims, mineral rights, education, economic development, energy.

"Our old friends are gone - or going. We have gound no new ones. We need to develop strategies and to form alliances, not just with each other, but with individuals, organizations and groups in the nonIndian world."

What the conference organizers say they hope to achieve by its end tomorrow is a sense of agreement on a nationwide plan of action to protect Indian interests in those areas. To that end, they have scheduled a series of discussion groups that are to address the basic question of the rights of native Americans within this nation.

National media attention has been drawn to this arid and rugged reservation headquarters on the Arizone-New Mexico border, where rocky outcrops break this sparse, yet awesome, land.

Many here wear tribal dress - turquoise is in abundance, set in silver, and Navajo dresses are common. There are moccasins and braided hair as well as blown-dry haircuts and slacks that flare over platform shoes.

Security is strict, and among those on patrol are a Navajo tribal policewoman on her first day of duty at the Navajo community center that has been converted into a convention hall with an assortment of banners proclaiming the tribes that are in attendance.