WASHINGTON (AP) _ Federal land managers are largely ignoring congressional directives to designate areas of ''critical environmental concern'' on the vast public lands of western states, according to an environmental group.

Only in Oregon and California have officials of the Bureau of Land Management, part of the Interior Department, given priority to establishing such areas under the 1976 Federal Land Policy and Management Act, said the report from the Public Lands Institute issued last week.

The institute is part of the Natural Resources Defense Council.

Such a designation in land-use plans may be given to tracts where ''special management attention is required ... to protect and prevent irreparable damage to important historic, cultural or scenic values, fish and wildlife resources or other natural systems or processes, or to protect life and safety from natural hazards,'' in the words of the statute.

Areas of critical environmental concern that have been established range from tracts for protection of rare plant species to a Wyoming area dangerous to use because of working oil wells and leftover contamination and debris.

The designations may be in addition to other classsifications made by Congress, such as wilderness areas, or by the bureau, such as an ''outstanding natural area'' for which special management policies are adopted.

Bureau of Land Management authorities in California have designated 91 areas of critical environmental concern covering 778,276 acres. Their Oregon counterparts have listed 63 areas covering 240,061 acres, said the report written by the institute director, Charles H. Callison, and associate Ann P. Tobin.

But none had been designated in Arizona and Alaska, and far fewer in other states: 12 in Colorado, 186,802 acres; eight in Idaho, 229,018 acres; one in Montana, 12,048 acres; four in Nevada, 1,479 acres; seven in New Mexico, 19,392 acres; seven in Utah, 89,231 acres and 13 in Wyoming, 208,385 acres.

Based on the pace in California, the nation should have 1,199 ACEC areas, Callison wrote.

Callison, who toured Bureau of Land Management offices in the West for his report, cited lack of interest at headquarters in Washington and the wide latitude given the bureau's state directors as factors in the lack of critical environmental area designations.

He also cited the use of specialists for other work believed more important under tight budgets and ''reflexive'' opposition by mineral and livestock interests even though ACEC designations do not necessarily restrict mining or grazing.

The acting state director for Montana, Marvin LeNoue, wrote in explaining Bureau of Land Management policy in his state to Callison: ''We do not believe in a numbers game where more is better or that large numbers of designations equate with a positive program.''

In public comment sessions on a planning area in Montana, ''the public supported Outstanding Natural Area designations over ACEC as the best management alternative,'' he said.

There was no answer at the home of a Bureau of Land Management spokeswoman in Washington on Sunday.