Confidence in the manufacturing sector has risen against expectations, showing resilience in the economy — and perhaps bolstering the case for Prime Minister Shinzo Abe hiking the consumption tax again next year.

The "tankan" index of large manufacturers rose to 13 in September from 12 in June, the Bank of Japan said Wednesday, above a median estimate of 10 in an independent survey of economists. The index is forecast to remain at 13 in December.

"Business conditions have improved in contradiction of market expectations. This is a positive surprise," economists at SMBC Nikko Securities Inc. said in a report.