A top Carter administration budget official estimated yesterday that $16 billion could be cut from federal deficit through the use of new tools to collect delinquent government debts.

Wayne G. Granquist, associate director of the Office of Management and Budget, told a Senate governmental affairs subcommittee that the Internal Revenue Service believes it could collect $10 billion of the $13 billion in deliquent taxes due during the fiscal year that ended Sept. 30 and $6 billion more in defaulted loans and overpayments from the same budget year.

Sens. Charles Percy (R-Ill.) and James Sasser (D-Tenn.) held the hearing in support of their bill to allow federal agencies to report the names of deliquent debtors to credit bureaus.

Granquist noted in his testimony yesterday that most government debt collection systems are so antiquated many agencies can't keep an accurate account of how much they are owed. Most program managers have given a low priority and few resources to collecting debts, he said.

Percy and Sasser said they hoped the incoming Reagan administration would commit more manpower to debt collection.Granquist said the departing OMB team would recommend additional resources for the program in the fiscal 1982 budget it is now preparing.

Granquist, who was a Connecticut banker before joining OMB, said he recognized that many government programs have social purposes that make them high risk. "If it's a grant it should be called that," he said. "If it's a loan, the government should carry forth policies to make sure it's a decent loan."

A recent OMB study showed that the federal government is owed $175 billion.