The Carter and Kennedy camps have agreed in principle on a plan for dividing up seats on a key drafting committee whose 15 members would then write a compromise Democratic Party platform, sources in the Carter campaign said yesterday.

If this plan holds up, the two factions in the party would work out their differences in time to complete a mutually acceptable party platform by June 24, long in advance of the Democratic National Convention scheduled to begin Aug. 11.

This would mean the Democrats could avoid an embarrassing and divisive platform fight at the convention, an outcome ardently desired by President Carter's campaign officials. However, a compromise platform could be expected to depart in some ways from Carter administration policies.

A key Kennedy aide said last night that final details of this plan remained to be worked out. He added that an important issue was the degree to which "the candidate" agreed to be committed by the platform that is eventually approved.

Paul Kirk, director of the Kennedy campaign, added that he would meet today with Richard Moe, Vice President Mondale's principal political aide, to try to work out details and membership of the drafting committee. Kirk said Moe has proposed a committee composed of nine Carter backers, five Kennedy supporters and one person acceptable to both organizations. Kirk said he would ask for a larger representation for the Kennedy camp.

The Carter campaign argues that the committee should reflect the number of delegates committed to Carter and Kennedy. According to the latest UPI delegate count, Carter will have 59 percent of the delegates at the convention, and nine out of 15 members of the drafting committee would be 60 percent.

Kirk said the offer of five seats to the Kennedy camp was not an act of generosity, but "the least they could offer" given the results of the primaries and caucuses.

Ultimately, sources in both camps agreed, the prospects for avoiding a bloody platform fight would depend on Kennedy's determination to press his differences with Carter. The two sharply disagree on numerous basic issues, and there seems little prospect that Carter would accept many of Kennedy's specific positions that flatly contradict his own.

Both sides hope to work out the membership of the drafting subcommittee before Thursday, when the full platform committee is scheduled to convene in Washington to hear testimony from the Kennedy and Carter campaigns, as well as from numerous Democratic members of Congress.