President Carter made public his 1979 income tax return and a net worth statement yesterday and, through White House press secretary Jody Powell, accused Sen. Edward M. Kennedy (D-Mass.) of failing to disclose fully his financial status.

The documents showed that Carter's net worth slipped below $1 million last year and that his income declined compared with 1978. The declines were largely associated with losses incurred by the Carter family peanut warehouse business, the principal asset in a trust managed for the president by his close friend, Atlanta lawyer Charles H. Kirbo.

According to the tax form, Carter paid $64,944 in federal income tax last year on an adjusted gross income of $193,823. But because an excess amount for taxes was withheld from his salary and because he made an estimated tax payment during the year, the president is due a $16,703 refund from the Internal Revenue Service.

In 1978, Carter's federal tax bill was $89,805 on an adjusted gross income of $254,029.

The president's net worth, a little more than $1 million at the end of 1978, declined to $893,304 by the end of last year, according to the documents. 1Carter listed assets totaling $1,054,178 and liabilities of $160,874.

Carter's net worth and tax statements were made public on the day all taxpayers faced the IRS deadline for filing their 1979 tax returns. While Republicans on Capitol Hill used the occasion to criticize the president's tax and budget policies, Powell sought to focus attention on Democratic presidential hopeful Kennedy.

Kennedy has made public his 1978 tax return and filed the yearly financial disclosure statement required of members of Congress. But, suggesting that the disclosures form, which is less specific than Carter's, is inadequate, Powell said, "This would not seem to be the degree of disclosure one would expect from one seeking the highest office in the land."

Jim Flug of the Kennedy campaign said the senator's 1979 tax return would be made public as soon as it can be duplicated, and he dismissed Powell's comments as a "diversionary smoke screen" timed to affect next week's Pennsylvania primary.

"The people of Pennsylvania and the entire nation are more interested in the price of hamburger and the cost of a mortgage than they are in last-minute cheap shots by Jody Powell," Flug said.

While Carter's cash holdings rose last year, from $228,750 to 228,218, his overall net worth declined because of a $255,013 drop in the estimated value of the personal assets trust administered by Kirbo. Valued at $784,345 at the end of 1978, the trust was listed as worth $529,332 a year later.

The president's income tax form also showed a $79,609 deduction because of operating losses by the trust last year. Powell blamed the losses largely on soaring interest rates that pose an equally serious political problem to the president.

Powell said the Carter family peanut business has borrowed a substantial amount for equipment at an interest rate 1.5 percentage points above the prime rate -- the rate banks charge their most preferred customers. As the prime rate soared last year, the president, like other businessmen with large amounts of borrowed capital, was forced to make substantially higher interest payments, Powell said.

Such interest payments are tax deductible.

In addition to his $200,000 annual salary as president, other major portions of Carter's income included $22,670 in interest from his cash holdings and a $8,181 dividend from his personal assets trust.

Carter's adjusted gross income on which he paid taxes was less than his total income largely because of an operating loss by the personal assets trust, which reduced his taxable income.

For most of last year, the president was also allowed to keep and treat as income the unspent portion of a $50,000 expense allowance. However, the law dealing with this has been changed, and since October Carter has been required to return to the treasury any unspent expense funds.

The tax form showed that the president did not entertain lavishly last year with his own money. He claimed $1,703 in employe business expense deductions, including $534 for meals for guests, $639 for staff parties and $288 for gifts.

Carter claimed $43,090 in deductions. These included $14,414 for state and local taxes, $3,186 in interest expense and $13,300 in miscellaneous deductions, including $11,690 in professional services by lawyers and accountants.

The president's charitable contributions last year totaled $15,438, down slightly from $18,636 during 1978.