The lack of child care in businesses costs the economy about $3 billion a year, jeopardizing economic growth as more women are needed to enter the work force, the head of a national child care coalition said Saturday.

Declining birth and labor force growth rates mean that two-thirds of new jobs will have to be filled by women between now and 1995, said Barbara Reisman, executive director of the Child Care Action Committee in Washington, D.C."It's fairly clear that the lack of child care is an impediment to entering the work force," said Reisman, in Boston for a conference of the Massachusetts Association of Day Care Agencies.

Reisman's organization late last month issued a report calling on the federal and state governments to play a greater role in working with businesses to increase child care efforts such as capital grants to employers for child care programs and parental leaves.

"Only 7 percent of American households now fit the Beaver Cleaver family's mold of breadwinning father and at-home mother," the report said. "As female labor force participation rates continue to climb, the demand for child care will grow too."

The number of companies providing some form of child care has increased from 110 to 3,500 in the past decade, according to the study, but that still accounts for just six in 10,000 businesses.

The $3 billion figure cited by the report is based on child care-related work absences. Reisman said it does not include estimates of lower productivity because of parents' worries over a child, lateness, work-force departures or shorter work days.