WASHINGTON (AP) _ Presidential candidates are off to the start of the 1988 campaign fund- raising marathon, with two reporting receipts of more than $1 million already, as several others have yet to begin filing disclosure statements.

The candidates who had set up official campaign committees by the end of the first quarter of the year, March 31, were required to file financial reports on Wednesday with the Federal Election Commission.

On the Democratic side, Sen. Joseph Biden of Delaware showed receipts of $1.7 million so far, with $1.5 million available at the end of the quarter.

Former Arizona Gov. Bruce Babbitt raised $824,777, with $269,430 in cash on hand.

Rep. Richard Gephardt of Missouri collected just over $1 million, with $525,429 on hand at the end of the quarter.

Unlike the other two, who just got their fund-raising operations in gear recently, Gephardt had a presidential exploratory committee in place last year, which reported raising another $91,676 by the end of the year.

On the Republican side, Sen. Bob Dole of Kansas voluntarily filed a financial statement for his exploratory committee Wednesday, although candidates are only required to report when they have an actual campaign committee in place.

Dole showed receipts of $626,689 since setting up his exploratory committee earlier this year, with $208,742 still available in cash on hand.

Reports from other presidential contenders did not arrive at the FEC on Wednesday, officials said.

Former Delaware Gov. Pierre S. du Pont, the first major party candidate to declare himself officially in the race, had showed recipts of $886,522 when he filed his year-end report for 1986.

The reports filed Wednesday showed the candidates were concentrating most of their spending in Iowa and New Hampshire, the traditional starting-gate states by virtue of their caucus and primary in early February.

Candidates are required to account for how much money they spend in each state, and must stay within state limits in order to qualify for federal matching funds for their campaigns.

The candidates must stay within an overall spending limit as well, which in 1988 will be nearly $27 million for the primaries.

The nominees of each party will have their general election campaigns completely funded by the federal fund that is supported by voluntary $1 check- offs on individual tax returns.