Prince George's County Executive Winfield M. Kelly Jr. asked the County Council yesterday to raise the real estate property tax rate by 4 cents instead of cutting it by 10 cents as he had previously proposed.

Kelly acted in the expectation that a petition drive to block a proposed 10 per cent tax on telephone service will succeed, depriving the county of $7 million in revenue that would have made the property tax cut possible.

A group calling itself Prince George's Citizens Against Nuisance Taxes argues that the phone tax would be an unfair burden on low-and middle-income residents and already have submitted petitions bearing 6,000 signatures in their effort to force the tax to referendum in November, 1978.

If the group files another 6,000 names by July 1, the tax law will be blocked for almost a year and half until voters decide whether to approve or reject it.

A 4-cent increase in the property tax rate would set it at $3.41 per $100 of assessed valuation, increasing the $1,011 tax paid last year on a home valued at $60,000 by $12. The original proposal to cut the rate by 10 cents would save the same taxpayer $30.

Many county taxpayers could expert higher tax bills, anyway, since the assessments of their homes have been increased in the past year.

Although Kelly said he expects the petition drive to succeed, he included a clause in the resolution he submitted to the Council that would allow the Council to levy the telephone tax increase if the drive fails.

The resolution says that if the telephone tax goes into effect, the county will "return" to property taxpayers the difference between the amount they oay at the $3.41 per $100 rate and the lower rate originally planned. This would be done, Kelly said, by sending checks to taxpayers.

The telephone tax on an averange monthly phone service bill of $12.50 would cost residential users about $15 a year. In addition to a 10 per cent levy on residential phone service, the new tax would impose a 4 cent message unit tax on commercial and industrial telephone users.

The Council is required to set the property tax rate by June 30, the day before the petitioners' deadline of July 1, and so is likely to operate on the assumption that the telephone tax will be blocked and the revenue from it will not be available to help fund the county's $414 million budget for the 1977-78 fiscal year. STCouncil members generally are unhappy over the petition drive and the fact of lower taxes. Next year is an election year.

"The people [who signed the petition] are getting snookered," declared Council Chairman William B. Amonett. "They can't know all the facts. We are trying to create a more equitable tax by taxing all county users, even the federal government, through this [phone] tax, instead of relying solely on the property tax."

Kelly said yesterday he would like the petition drive dropped and that one of his aides had talked to Tim Maloney, a leader of the drive.

Maloney said he would discuss Kelly's offer with other leaders of his group. "But," he added, "I'm mystified why they are doing this so late in the game." He said didn't think the petition drive will be dropped.