President Reagan yesterday pressed the Democratic-controlled House to "do what is right" and "resist the Soviets' brazen attempt to impose communism on our doorstep" by voting $27 million in nonmilitary aid this week for the anticommunist rebels in Nicaragua.

Calling the Nicaraguan con- tras "freedom fighters," the president in his weekly radio address, broadcast from Camp David, declared, "We must not sit by while the Nicaraguan people are sad- dled with a communist dictatorship that threatens this entire hemisphere.

"A House vote for humanitarian aid to the freedom fighters will send a strong bipartisan message that we will not tolerate the evolution of Nicaragua into another Cuba nor will we remain with our heads in the sand while Nicaragua becomes a Soviet client state with installations constructed for use by the Soviet bloc."

Last Thursday, in a victory for the president, the Republican-controlled Senate approved, 55 to 42, a compromise providing $38 million for nonmilitary aid, such as food, clothing and medicine, to the contras. The aid -- $14 million this year that had been "frozen" in an earlier dispute and $24 million next year -- would be administered by the Central Intelligence Agency as the administration wanted. But the aid could not be used for guns, bullets and other weapons.

In the House, where the majority Democrats have repeatedly rejected aid to the rebels, most recently on April 25, the president called for passage of a proposal sponsored by House Minority Leader Robert H. Michel (R-Ill.), Rep. Joseph M. McDade (R-Pa.) and Rep. Dave McCurdy (D-Okla.).

It would provide $27 million in nonmilitary aid through March 31, 1986, but bar both the CIA and the Defense Department from being designated as the agencies to administer the money.

Administration sources have said they hope that if the Michel amendment is passed, CIA handling of the funds will be restored in a House-Senate conference. The Michel amendment also softens an existing ban on direct, or indirect military or paramilitary aid to the rebels, by allowing the CIA to provide intelligence information to the rebels.

In addition, the Michel amendment provides $2 million to foster talks that could lead to a negotiated settlement of the Nicaraguan struggle. The president said yesterday he favors such talks leading to "a negotiated settlement, national reconciliation, democracy and genuine self-determination for the people of Nicaragua."

The Michel amendment faces sharp Democratic opposition. Democrats are expected to try to limit aid to $14 million, to direct it not to the rebels but to needy refugees outside Nicaragua, to delay the release of the funds to see if negotiations for a settlement work, and to restore the full force of the ban on direct or indirect military or paramilitary aid.