WASHINGTON (AP) _ President Bush asked Congress today to boost incentives for saving by cutting taxes on capital gains, creating a tax break for long-term accounts and allowing Individual Retirement Account withdrawals for some homebuyers.

His proposed budget for the bookkeeping year that begins Oct. 1 calls for no general tax increase. It includes more targeted tax reductions than tax increases.

The biggest new burden would fall on several million employees of state and local governments, who are not paying into the Medicare system. Bush proposed that all such workers hired before April 1, 1986, be required to pay that tax, which is 1.45 percent of the first $120,000 of wages.

Congress has rejected that proposal in each of the last several years. State and local workers hired since April 1, 1986, already are paying the tax. The extension would bring in $7.1 billion over the next five years.

In a written message, Bush said his savings incentives would enhance the nation's potential for long-term growth. All three proposals failed in Congress last year as Congress negotiated a long-term, deficit-cutting agreement with the administration.

The president proposed to:

-Allow 30 percent of capital gains, which are profits from the sale of investments, to be excluded from taxation for property owned more than three years. Twenty percent of gains from two-year property and 10 percent from property owned a year or longer would be excluded.

Capital gains now are taxed at a maximum rate of 28 percent, although higher-income people pay a rate of 31 percent on a part of their wages and other income. The proposal would cut the maximum capital-gains rate to 19.6 percent.

-Permit a person to set aside up to $2,500 a year in a special savings account that, if held for more than seven years, would produce tax-exempt interest. The contribution itself would be fully taxable. The special account would be limited to individuals with annual incomes of $60,000 or less and families with $120,000 or less.

-Allow a penalty-free withdrawal of up to $10,000 from an Individual Retirement Account to help a family buy its first home.

-Extend several tax breaks that are due to expire on Dec. 31, including those for business research and investors in low-income rental housing.

-Create tax incentives to lure employers to locate in up to 50 economically deprived ''enterprise zones.''

-Increased user fees to bring in about $12 billion over the next five years. These include a requirement that veterans pay a greater share of their medical bills for illnesses not connected to their military service or if they have a service-connected disability that is rated 40 percent or lower.

User fees charged by the Army Corps of Engineers would be expanded to cover overnight camping.

P-DS-02-04-91 0944EST