In a sharp exchange of words on the floor of Parliament yesterday, a leader of a dissident faction in Prime Minister Morarji Desai's Janata Party denounced Desai for his tough warnings against unruly antigovernment demonstrations.

It was the latest display of open animosity within India's ruling party.

Former Health Minister Raj Narain, forced from the Cabinet along with Home Minister Charan Singh by Desai in late June, accused the 82-year-old prime minister of abandoning his belief in non-violence by vowing to deal firmly with rowdy demonstrators.

Desai told the lower house of Parliament in response: "If he (Narain) supports violent action, let him say so. Then I will deal with him also."

The sharp exchange came during a discussions of Sunday's violent protest outside the prime minister's residence by a group of farmers angered at Desai's refusal to intervene in a caste dispute.

About 4,500 farmers, mostly members of the relatively low Hindu caste of Jats, gathered at Desai's residence to protest the leasing of farm land in the village of Kanjhawala to Untouchables, the lowest caste. The leases expire in 1980, but the Jats, who make up the majority in Kanjhawala, 19 miles west of here, want the land back now.

While Desai appears to have won the first round in the challenge to his control by Singh and Narain, the battles appear far from over. Efforts at reconciliation so far have failed and Singh has already announced that he will continue his fight against the present leadership from within.

Although he is still recuperating from a serious heart attack two months ago, Singh remains a formidable figure with his power base in key northern states. Nevertheless, he has been unable to unite his own party behind him.

Desai is also having his problems in the multi-factioned Janata Party over the firing of Singh and Narain. While the two were fired a month ago, party affairs have not settled down enough to allow naming of replacements.

For all their internal divisions, however, the Janata Party maintains a comfortable 303-seat majority in the 544-seat lower house of parliament. Singh or any other would-be defector would have to take substantial numbers with him to affect the party's hold on power and possible force premature elections. So far, there are no signs anyone could or wants to do that.