Banished dissident leader Andrei Sakharov is now living in a four-room apartment in the regional auto-manufacturing city of Gorki with his wife and an uninvited woman "companion," friends of the family said here today.

Sakharvo's wife, Elena Bonner, successfully called Moscow from a telephone in the city -- 250 miles east of Moscow and closed to foreigners -- and managed to provide a brief description of their new life before the line was cut, the sources said.

Sakharov, a 1975 Nobel Prize laureate, was sent by the KGB secret police Tuesday to internal exile for an indefinite period.In a separate conversation with friends in Moscow, Sakhavrov, 58, said that his wife is not included in the banishment order.

Bonner, 57, herself an outspoken activist, probably will be allowed to travel to Moscow and elsewhere in the country in the future.

In it assumed the women companion is a secret police agent assigned to live with the Sakharovs and report on their activites.

The same sources close to the Sakharovs said they believe the physicist who won the peace prize for advocating individual freedoms in this authoritarian state, may find a job in a scientific institute in Gorki. As a member of the prestigious Academy of Sciences, Sakharov would have access to this kind of job, despite his banishment and the real threat of grave official charges the KGB may be holding over him.

Eighteen friends and associates of Sakharov here condemmed his exile today calling him "the conscience of our country." Writer Lev Kopelev, a close supporter who himself spent years in forced labor camps, said the state "made this reprisal because Sakharov fearlessly spoke the truth, making uncomfortable a government that. . . pursuses all those who try to defend the rights of man."

These dissidents believe the secret police acted now against the Sakharovs for two reasons -- to rebuke President Carter for his Afghanistan invasion retaliation and to uproot from Moscow the government's staunchest internal tormentor prior to the Olympics, which the Soviets want to use as a showcase for the fiction that perfect unanimity exists in the Soviet Union. a

The new Sakharov apartment in Gorski apparently is about double the size of most apartments in this housing-short nation -- another small sign of the remarkable status that even an academician accused of traitorous activities may retain.

Meanwhile, in a bold example of their resilience, Moscow activists of the Helsinki human rights monitoring group today denounced the Kremilin for destroying the independence of Afghanistan, and called on world opinion to fight for the withdrawal of Soviet troops.

They declared that the Kremlin's denial of basic human freedoms to its own people posed a threat not only to neighboring states, but to all mankind. The statement, signed by Bonner and three others, also carried the "supporting signature" of Sakharov, although he is not officially a member of the group.

"A mighty superpower with a population of 260 million is suppressing the independence of Afghanistan, a nation of 17 million, while the Soviet mass media claim that our people are giving their unanimous support," the group asserted.

"But in reality, people in the Soviet Union have neither truthful information nor the right to express their opinion, even on such an arbitrary step by the government as the start of a new, unjust war," said the statement.

The cosigners included retired lawyer Sofia Kalistratova; Ivan Kovalyov; and Malva Landa, another Helsinki group member who was exiled to eastern Siberia several years ago. Sources said Sakharov telephoned friends from Gorki, and told them to release the statement. It had been drawn up Monday, the day before the dissident physicist was seized and exiled.

The current secret police drive that in the past three months has brought the arrest of more than 40 dissidents across the country, continued yesterday with the arrest of two contributors to a clandestine journal of dissident politcal thought, called "Searches." Sources said Yiktor Sokirko and Yuri Crim were taken off by police yesterday, and their homes and those of three other contributors to the magazine were searched.

The Helsinki watch group was set up to check Soviet compliance with human rights provisions of the 1975 accord on Europeans security signed by the Soviet Union, and 33 other nations. The group said that agreement confirmed an indissoluble link between peace and human rights. "It is the absence of basic human rights that give the Soviet leadership the ability to decide without any form of control not just the future of our country, but of all humanity."