Rep. Joseph P. Kennedy II, who spent $1.8 million last year in his successful bid to replace retiring House Speaker Thomas P. O'Neill Jr., remains $227,272 in debt despite heavy fundraising, recent campaign finance reports show.

Although the Eighth District Congressman raised more than $336,000 in the first six months of 1987, he was able to pay off only about one-third of his campaign debt of about $360,000. The Federal Election Commission (FEC) reports show that Kennedy spent $132,600 during the first half of this year, paring down that debt.

Kennedy aides said they anticipated that it would take time to pay off this debt, partially because many contributions were earmarked for Kennedy's 1988 re-election bid. Consequently, Kennedy could not use the funds toward cutting down his debt. Kennedy now has $96,240 in his campaign coffers, up from $21,244 at the end of last year, the reports said.

In addition, Kennedy has experienced intensified competition for the money of Massachusetts taxpayers, especially from presidential aspirant Gov. Michael S. Dukakis, who has already soaked Americans for a whopping $4.6 million.

But eliminating Kennedy's 1986 debt is the campaign's top priority, Kennedy aides said. "[Kennedy], like everyone, wants to pay his bills as soon as possible," said fundraiser Elizabeth A. Lonergan.

Kennedy hopes to have the debt erased by the end of this year, Kennedy aide Charles McDermott said.

Most of the 1987 events have been bringing in $10,000 to $25,000. The son of Sen. Robert F. Kennedy has not planned any large events similar to last year's cookout at the Kennedy compound on Cape Cod that brought in some $75,000, McDermott said.

The bulk of Kennedy's remaining debt is comprised of three loans he took out during the campaign to defeat a field including a dozen Democratic contenders in the primary and a wealthy Republican businessman in the general election.