The House Veterans' Affairs Committee yesterday voted to increase GI Bill benefits for Vietnam veterans by 6.6 per cent.

The committee also voted to deny automatic benefits to many whose less-than-honorable discharges have been upgraded under the administration's Vietnam "amnesty" program. Under the committee proposal, the Veterans Administration would determine whether benefits would be awarded. The test would be whether "honorable service" was rendered.

The Committee then sent to the floor its version of the "GI Bill Improvements Act of 1977," which would cost an estimated $438 million in increases in educational benefits. About 1.8 million veterans are expected to participate in the GI Bill program next year.

The increase would translate into larger monthly checks. For example, a single veteran attending an educational institution full time now receives $292 each month, which includes tuition allowance. If the 6.6 per cent increase measure now awaits action by the full Senate. The Senate GI legislation differs from that of the House by providing for accelerated tuition payments for veterans attending schools where tuition costs exceed $1,000 per year.

The acceleration plan is a way of dispensing GI Bill benefits faster. Veterans attending expensive private schools do not now received enough money each month to cover tuition. Acceleration of payments to them, according to proponents of the plan, would help alleviate this problem without increasing the total paid through the GI Bill since accelerated payments would end sooner.

The amendment, which makes it easier for veterans in northern and northeastern states to pay the higher schooling costs in those states, is sure to be a point of contention when conferees from both houses meet to resolve differences later this year. The House Veterans' Affairs Committee will hold hearings on tuition equalization and other matters in September. But, according to Rep. Robert W. Edgar (D-Pa.), "that's too late to do anything on it."

For veterans seeking upgraded discharges, the proposed bill does not go as far as the hotly debated amendment, offered by Robin Beard (R-Tenn.), which would deny benefits to any veteran whose dishonorable or general discharge is upgraded under the administration program. The measure voted on today would provide a two-step process by which the Veterans Administration would ultimately determine whether benefits would be awarded for "honorable" service.

Edgar, who opposed the Beard amendment during hearings earlier this summer, surprised many colleagues by supporting yesterday's committee measure.

"I think the President's discharge review program is fair and working well," he said later, "but I saw the legislative writing on the wall. I realized that the Senate and House could be a lot more vindictive and harsh in their language."