A special House subcommittee yesterday voted to allow wages of up to $10,500 a year for some public service jobs for welfare clients under President Carter's omnibus welfare revision bill.

The $10,500 figure, to be permitted for a relatively small number (15 percent) of supervisory jobs, would apply when the new program became fully effective in 1982, according to the subcommittee vote.

Most public service jobs under the program would pay between $7,000 and $9,200 in 1982, depending on local wage scales. But the subcommittee, led by Rep. Augustus F. Hawkins (D-Calif.) recommended a $10,500 maximum so that jobs in high-wage areas like Detroit, the District of Columbia and San Francisco would be paid closer to the level received in private industry or regular city jobs.

The permissable scales represent a substantial revision of Carter's initial proposal to create over 1 million public service jobs at the minimum wage ($7,000 in 1982) for welfare clients capable of working but unable to find private jobs.

Labor unions, led by the American Federation of State, County and Municipal Employees and the AFL-CLO, argued that wage scales are much higher than $7,000 in many areas and that the bill would therefore create a pool of low-wage "welfare" labor that could undercut wage scales in those areas and take jobs away from existing workers.

Spokesmen for AFSCME and the AFL-CIO said they are still not happy with the wage-scale provisions because by 1982, wage levels in ordinary jobs in many localities will exceed even the 10,500 welfare-job maximum. They said the average wage and maximum are simply too low.

However, both the Carter administration and Hawkins declined to go any higher. One official pointed out, "These are special jobs for welfare clients," not permanent new jobs. Under the subcommittee decision, a welfare client could keep the job for only 18 months during which, it is hoped job would be learned.

In another action, the subcommit-skills needed to optain a non-welfare tee, reversing itself fat the union's request, endorsed and amendment by Charles B. Rangel (D-N.Y.) allowing welfare families to collect full benefits as soon as they get on the rolls instead of reducing the benefits for the first five weeks while any employable adut seeks a job.