The number of new condominiums put on sale in the Tokyo metropolitan area increased 13.1 percent in August from a year earlier to 4,431 units, the third consecutive monthly gain, a private research institute said Wednesday.

The Real Estate Economic Institute said the rise reflected a rush by developers to put up condos in time for buyers to move in by next June, the deadline for making use of a tax break on mortgage loans.

Of the new condos, 3,622, or 81.7 percent of the total, were sold during the reporting month, up 8 percentage points from the year before, while 1,561 were sold on their first day on the market.

The average price of a unit was 39.62 million yen, up 3.55 percent, the institute said.

The number of new condos put on sale so far this year reached 60,338, a record for the eight-month period.

An institute official said the supply of new condos for the whole year is likely to hit a record 96,000, as marketing of new condos is likely to peak in October and November.

In the Kinki region, 1,402 condos were put on sale in August, down 11.4 percent from the year before for the first decline in five months.

The proportion of those signed up during the month fell 0.3 point to 71.3 percent, but the average price rose 2.9 percent to 33.5 million yen.

An official at the Osaka office of the institute predicted that the market is likely to be affected by higher interest rates from October, in the wake of the Bank of Japan's decision Aug. 11 to scrap its "zero-interest-rate" policy.