The Treasury will have to borrow $46.5 billion to keep the government running during the current quarter, about $5 billion more than tax experts predicted three months ago.

During the next two weeks, as part of its regular quarterly financing, the government will raise $13 billion, $8.4 billion of it new cash.

The Treasury estimated net market borrowing for this calendar year at $152 billion, as compared with $99 billion borrowed in calendar 1981.

The department also announced that next Monday it would introduce a new type of savings bond that would carry a competitive interest rate for purchasers who hold them for at least five years.

Beryl Sprinkel, undersecretary of the Treasury for monetary affairs, said the higher projected borrowings are due to the continuing impact of the severe recession.

Lower employment and production reduce tax receipts at the same time that the government's expenditures for programs like unemployment insurance and welfare are on the rise.

Nevertheless, Sprinkel told reporters yesterday that there "are an increasing number of signs that we are in the recovery phase."

Furthermore, Sprinkel said, he and other members of the administration are convinced that the Federal Reserve Board, the nation's central bank, has not changed its policies in order to bring down interest rates, but has made a temporary adjustment in the amount of attention it will pay to the growth of the money supply for the next few months.

For the last three years, the Fed's policies have focused primarily on keeping the rate of growth of the money supply within targets. But for the next few months, Sprinkel said, the money supply figures will be distorted because of the billions of dollars of maturing All-Savers certificates and the "impending creation of a new bank account" designed to permit banks to compete with money market mutual funds.

But William Niskanen, a member of the president's Council of Economic Advisers, said earlier yesterday that it is not clear whether the central bank has made a temporary change in policy because of technical problems or a fundamental policy shift designed to bring down interest rates.

Reuter's News Service reported that Niskanen told a meeting of the U.S. Chamber of Commerce that it is "very difficult to get the Fed to state its policy clearly. There may already have been a major policy shift."

He said that if the Fed changed to an easier money path, as sources say it has, then the Fed would be buying short-term gains, but would eventually abort the recovery. "We in the administration are just as confused as the markets on whether there has been a substantial policy change," Niskanen said.

Sprinkel said that as part of its regular quarterly refunding it will auction:

$6 billion in three-year notes, with a minimum denomination of $5,000 on Wednesday.

$4 billion of 10-year notes, with a $1,000 minimum denomination, on Thursday.

$3 billion of a 30-year bond, with a minimum denomination of $1,000 on Nov. 9.

The new savings bond will carry an interest rate equivalent to 85 percent of the average interest rate on five-year Treasury bonds during the previous five years.

In no case, however, will an investor receive less than 7 1/2 percent, even if interest rates dip to 4 percent. Current owners of savings bonds will be guaranteed 9 percent if they hold them another five years.