With the Soviet military ensuring his immediate survival, new Afghan President Babrak Karmal -- apparently at Soviet insistence -- is taking steps to broaden his domestic political base.

For the first time since a series of communist coups starting in April 1978 nonmembers of the communist People's Democratic Party of Afghanistan have been appointed Cabinet ministers. In addition, the Afghan military, neglected under the previous two governments, now is represented heavily in the Cabinet and the main executive body, the Presidium of the Revolutionary Council.

These measures may satisfy the Soviet desire to expand the government's political base, observers here say. But the new appointments are unlikely to mollify either the country's Moslem insurgents or the large segments of society that oppose Soviet intervention here.

Moreover, some analysts say, the new government's effort to unify the two rival wings of the People's Democratic Party may create tensions in the Cabinet and Revolutionary Council. Some members of these bodies have been involved in purging and jailing others during the previous governments.

Despite a campaign of vilification against the government of his predecessor, Hafizullah Amin, Babrak has reappointed three members of Amin's Cabinet -- a move unlikely to dispel the widespread public conviction here that successive communist leaders are merely peas from the same pod.

Given these factors, the new Soviet-installed government may be shakier politically than even Moscow may realize. This could mean that backed by the force of an estimated 85,000 troops in Afghanistan, the Kremlin may have to pull some more strings before it finds a government it is comfortable with.

Analysts here say it is likely that the Cabinet and Presidium members were handpicked by the Soviets in the first place in an effort to unify the rival Parcham (banner) and Khalq (masses) wings of the People's Democratic Party.

"It is not they who united," said a senior diplomat. "It was the Russians who united them."

In an apparent effort to correct the neglect of the armed forces under the previous two governments, military men have been appointed to four of the seven places in the Revolutionary Council's Presidium. They are Col. Assadullah Sawari, Maj. Gen. Abdul Qader, Lt. Col. Mohammed Aslam Watanjar and Lt. Col. Gul Aqa.

Whereas Amin's Cabinet contained no members of the armed forces, five of the 20 posts in Babrak's are filled by officers. Sarwari, besides being vice president of the Revolutionary Council, is a deputy prime minister. Watanjar, in addition to his membership on the Presidium, is minister of communications. Col. Mohammed Gulabzoi is the new interior minister, Col. Sherjan Mazdooryar is transport minister, and Lt. Col. Mohammed Rafi holds the key defense minister's portfolio.

This makeup creates a pollibility for tensions. Sarwari,considered the second-in-command behind Babrak, was the chief of the secret police under the government of Nur Mohammed Taraki when three of the new Cabinet and Presidium members were relieved of their government posts and jailed in August 1978.

Among the three are Sultan Ali Kishtmand, who holds his old job of planning minister in addition to being a vice president of the Revolutionary Council and a deputy prime minister like Sarwari. Also jailed under Sarwari were Qader, then denfense minister, who reportedly was tortured severly, and Rafi, who was minister of public works under Taraki.

Ironically, Taraki, who emerged as president after the Soviet-backed coup of Arpil 1978 but was slain in Amin's coup in September 1979, is being billed now as a martyr by men who were purged under him. They include Babrak who initially was a deputy prime minister under Taraki but was soon sent into virtual exile as ambassador to Prague.

The new reverence for Taraki and the joining of rivals in the new government illustrate the contortions that Afghan leaders are being forced to go through to preserve a facade of continuity from the Taraki leadership to Babrak's while trying to focus blame for all ills on Amin's rule in between.

In addition to the three new government figures jailed under Taraki, four were forced to seek Soviet protection when they were purged after Amin came to power last year -- Sarwari, Gulabzoi, Mazdooryar and Watanjar. They sought refuge in the Soviet Embassy during the purge and may have been flown out to the Soviet Union. All have emerged in key positions in the new government.

Another possible source of tension in Babrak's administration lies between these men and three holdovers from the Amin Cabinet. They are the new minister of mines and industries, Mohammed Ismail Danish, and two members of Babrak's 57-member Revolutionary Council and 35-member party Central Committee: Dastagir Panjsheri and Shleh Mohammed Zeari.

The three new Cabinet ministers who have not been members of either the currently predominant Parcham facton of the People's Democratic Party or the Khalq wing represented by Taraki and Amin are Mohammed Ibrahim Azeem, the minister of public health, Fazal Rahim the minister of agriculture, and Mohammed Kahn Jalalar, the commerce minister. Jalalar is considered one of Afghanistan's great political survivors, having been commerce minister under the government of Mohammed Daoud before the April 1978 coup.

The only woman member of the Cabinet, Dr. Anahita Ratebzad the ministe of education, was ambassador to Belgrade when Babrak was the envoy to Prague.