Even as Congress is moving to provide an extra 13 weeks of unemployment benefits for the long-term victims of recession nationwide, a provision of last year's budget-cutting bill is about to take away 13 weeks of benefits in some states, affecting as many as 200,000 workers.

This provision, which Congress approved at President Reagan's request, is expected to knock anywhere from 7 to 12 states out of a program that gives workers in high-unemployment states who have exhausted their basic 26 weeks of benefits an extra 13 weeks, for a total of 39.

The states would revert to the basic 26 weeks on Sept. 25, less than six weeks before Election Day.

At present 27 states have unemployment high enough to qualify for the extra 13 weeks, and 510,600 workers who used up their initial 26 weeks are collecting the extended benefits, for which the federal government pays half the cost.

Under the new rules, however, a state will have to have higher unemployment than required now to receive the extended benefits, and some states that currently qualify will fall short.

States expected to "trigger off" include California, the most populous and President Reagan's ome state.

Not only will no new workers be eligible for extended benefits in these states, but workers now receiving such benefits because they have exhausted their basic 26 weeks will be dropped.

Ironically, this comes as Congress is considering bills under which workers in high-unemployment states who exhaust their basic 26 weeks plus the extra 13 allowed under existing law would be allowed 13 more, for a total of 52.

The House Ways and Means Committee has twice approved such legislation despite administration opposition, and at a hearing last week the chairman of the Senate Finance Committee, Robert J. Dole (R-Kans.), indicated that he, too, approves.

This extension, however, would not affect the triggering mechanism created in last year's budget bill, so the 52 weeks would be provided only in those states meeting the higher standards.

Under existing law, state insurance programs normally provide 26 weeks of unemployment benefits. Then, if a state's unemployment rate is sufficiently high, 13 weeks of extended benefits are available, paid half by the federal government and half by the state.

At present, a state becomes eligible for extended benefits in any week when "insured unemployment" or the unemployment rate of workers eligible for benefits has averaged at least 4 percent for 13 weeks and has risen at least 20 percent over the average for the same 13 weeks in the two preceding years. Alternatively, the state can qualify if "insured unemployment" is 5 percent even if there has not been a 20 percent increase.

The president last year proposed, and Congress agreed, to save money by raising these triggers this September to 5 percent (with 20 percent growth) or 6 percent without growth.

Maryland, Virginiaand the District don't meet even the present standards for participation; Maryland did, but just triggered off.

Of the 27 jurisdictions now in the extended program, at least 13 will not meet the new triggers if they have the same unemployment rates this fall as now, and a 14th, Montana, is so close it could easily slip below the line.

The 13 are Alabama, Arizona, California, Illinois, Iowa, Kentucky, Louisiana, Nevada, North Carolina, Tennessee, Utah, the Virgin Islands and Wisconsin.

Some of these may trigger off even under the old, easier trigger requirements in the next few months, so their loss of benefits wouldn't be attributable to the Reagan provision.

Others may have worsening conditions and stay on, and other states might trigger off.

Overall, unemployment insurance experts are estimating that at a minimum seven to 12 states will trigger off as soon as the new rules come into effect or shortly thereafter, and that up to 200,000 persons unable to find work will lose benefits as a result.