Japanese Premier Masyohshi Ohira, reelected today after a tense battle within the ruling Liberal Democratic Party, faces continued conflict that could impede his efforts to form a Cabinet promptly.

A month-long struggle within the conservative party leadership reached a climax in the parliament with former premier Takeo Fukuda challenging Ohira received 138 votes to 121 for Fukuda, while 252 legislators cast blank or invalid ballots.

It was the first time that Japan had seen two candidates from the same party contest in the Diet for the premiership.

The challenges to Ohira, 69 stem from that division of his party. Not only must he seek to mend the splits but he faces opposition parties invigorated by the sight of disarray in the dominant Liberal Democratic Party.

acknowledging the challenges, Ohira declared after his reelection that "I will face more difficulties now than I have in the recent days" of conflict with Fukuda.

Tonight, Ohira took the unusal step of calling personally on Fukuda, whom he replaced almost a year ago as premier, and another rival, former premier Takeo Miki. Normally, the victor receives his rivals.

Fukuda, 74, declared after his defeat, "The first round is over but the second has just begun."

With the rivalry unresolved, Ohira must seek by Wednesday if possible to name key party officials and form a Cabinet.

The challenge to Ohira came after he called elections last month to strengthen the party position in the Diet, only to see its voting strength reduced by one to 248.

Ohira acknowledged the error of pushing for unpopular tax changes but refused calls from Fukuda and Miki for his resignation.

Today's voting introduced a new factor in the troubled stance of the ruling party. For the first time, Ohira received electoral support of an opposition group, the New Liberal Club.

This group, which split off the ruling party in 1976 after the Lockheed payoffs scandal, said it received assurances from Ohira for two pet projects: reform of the party's close ties with big business and a tax cut for lower-and middle-income Japanese. The Liberal Club is not expected to be represented in the Cabinet, however.

Referring to the apparently widespread disillusion in the electorate with the falling out of the traditional leaders, Tokyo University professor of politics, Shiratori Rei, declared:

"People are so disgusted with this struggle because the fight . . . does not benefit the voters nor respond to their wishes. This was simply a power struggle within a party without any policy discussion."