Thousands of counties, cities and towns across the country may miss out on their share of $1.7 billion in federal revenue-sharing monies next month because they have failed to return forms assuring the government they will comply with the revenue-sharing law in disbursing the funds.

Because of a law passed last year, the government requires a new form from these local governments before they can receive federal revenues.

Of the 39,000 or so stale and local governments eligible for revenue-sharing grants, only 25,000 filed the required forms by yesterdays deadline, according to revenue-sharing officials.

Without forms signed by the chief executives of these states, cities and counties, the Treasury cannot send them revenue sharing checks on April 7. The forms were mailed Feb. 10.

A spokesman for the Office of Revenue Sharing said that, while yesterday was the official deadline for receipt of the forms which assure the localities will comply with the revenue sharing law, the government probably will accept forms until some time next week.

Undoubtedly, however, thousands of localities will miss out on the April payment because they failed to sign the new form - which was required by Congress last year when it extended the revenue sharing law until Sept. 30, 1980.

Officials have not decided whether to set up another, payout date for localities that realize they failed to send in their forms. Revenue-sharing payments are made each quarter.

Rather than provide states, cities and towns only with funds tied to specific programs, for the last several years the government has been granting billions of dollars which local governments can use as they see fit, within certain limitations.

When revenue sharing was extended through Sept. 30, 1980, at the end of last year, Congress added a strong civil rights provision to prohibit any discrimination in Programs which use revenue-sharing funds. The law also required chief executives of the 39,000 localities eligible for revenue sharing to sign forms stating they understood the law and will observe it.

In the past localities were required to make such assurances to the federal government on the same forms they filled out specifying how they used the money.

To complicate matters, local governments last November had to fill out compliance forms for a similar-named but separate antirecessionary revenue-sharing program which funnels money to states and localities hard hit by the economic downturn.

Congress has worried that high fuel bills, reduced taxes and big overtime payrolls caused by the severe cold this winter will force this spring in order to balance budgets. To counteract the problem, the House and Senate have approved a revised 1977 budget which boosts the anti-recession revenue-sharing funds available.

Treasury officials said yesterday that they did not know which localities have failed to reutn the proper forms and how much of the $1.7 billion the government planned to pay out next month will not be disbursed.

A spokesman for the Revenue Sharing Office said that financially pressed New York City's form was missing but that the agency understood a special messenger was bringing it down from New York last night.

The form perplexed at least one local official, who nonetheless returned it on time. Julia Lambie, chief executive of Osceola, N.Y., attached a note which read, "I hope to God it is made out right." If not, she asked the government to call. Osceola is due $3,633 in revenue-sharing funds for the first quarter of 1977.