The Zero Population Growth foundation is launching a nationwide campaign to generate public support for sharp cuts on both legal and illegal immigration to the United States.

In a fund-raising appeal signed by Paul R. Ehrlich, ZPG describes illegal immigration as a "human tidal wave" that is "depressing our economy and costing American taxpayers an estimated $10 billion to $13 billion a year in lost earnings and taxes, in welfare benefits and public services."

The letter refers only to "illegal aliens," but Melanie Wirken, ZPG's Washington lobbyist on immigration issues, says the organization also favors a "drastic reduction in legal immigration." Such a reduction would mean a major reversal of current U.S. immigration policy, which was significantly liberalized by a 1965 law abolishing the old system of "national origins quotas." During the past decade approximately 400,000 immigrants have legally entered the country each year.

ZPG's Washington headquarters has recently added a lobbyist so that Wirken can devote all of her time to immigration issues. This month the Rockefeller Brothers Fund is to vote on a proposal for a major grant to help finance ZPG's anti-immigration activities.

"Americans have traditionallly thought that immigration was good and that speaking against immigration was just like speaking out against motherhood and apple pie," Wirken says. "Over and over at congressional hearings, ZPG is the only group that raises a voice questioning the wisdom of letting in so many immigrants."

ZPG is a relatively small organization with a membership of about 8,500 - many of them academics and environmentalists - but it is influential beyond its numbers partly because it has developed such an active public relations and lobbying effort.

The group was originally formed in an effort to bring together groups favoring "no growth" economics with people who felt traditional family planning methods were inadequate to deal with what they considered a population crisis both in the United States and abroad. Ehrlich, author of "The Population Bomb," was one of ZPG's founders and is now its honorary president.

The significatn decline in the U.S. birth rate in recent years is one reason for ZPG's new emphasis on immigration.

ZPG has worked hard on behalf of state and federal bills to penalize employers of illegal immigrants and has strongly supported the efforts of out-going Immigration and Naturalization Commissioner Leonard Chapman to dramatize the extent of the illegal alien problem.

The ZPG fund-raising appeal quotes an often-repeated statement by Chapman that illegal aliens are holding at least 1 million jobs that pay more than the minimum wage - jobs Chapman and ZGP maintain could be filled by American citizens.

The 2 million jobs the government hopes to create is about the same number as the lowest estimate of jobs presently being held by illegal aliens, the letter notes. The discrepancy between Chapman's estimate of 1 million and ZPG's reference to 2 million jobs presumably refers to jobs being held by illegals that pay less than the minimum wage.

The ZPG assertion that illegal immigrants are costing American taxpayers billions of dollars in lost taxes and welfare benefits is contradicted by a major study for the Labor Department. The study of illegals apprehended by the INS was conducted by Linton and Co. and found that 77 per cent of those apprehended had paid Social Security taxes and 73 per cent had paid federal income taxes through withholding. Less than half of 1 per cent had been on welfare.

ZPG's position on immigration has fluctuated during the past two years. In 1975, the group prepared documents indicating stroung opposition to any amnesty for illegals already living in the United States. Wirken says ZPG can now support amnesty if it is tied to a package with stiff penalties for employers of illegals and with higher controls of illegals and with higher controls on the entry of tourists, students and legal immigrants from other countries.

Wirken says ZPG hopes to form an alliance with enviromental groups and labor unions that are concerned about the influx of illegal immigrants. Many AFL-CIO unions have supported bills to penalize employers of illegals, but no union has taken a position favoring a substantial reduction of legal immigrants.