Total defense spending would account for about 1.3 percent of projected gross domestic project in 2017, said Fu Ying, spokeswoman for the legislature. She was speaking at a news conference on the eve of the opening of the body's annual session.
The precise figure will be provided by Premier Li Keqiang in his address to the National People's Congress on Sunday morning.
Fu reiterated China's contention that its military was purely for defense and constituted a force for stability in Asia.
Depending on the final figure, this year's budget could mark the third consecutive year of declines in defense spending growth rates. The budget grew by 7.6 percent last year and 10.1 percent in 2015.
The increase of about 67 billion yuan ($9.7 billion) would push the total defense budget past the 1 trillion yuan ($145 billion) mark for the first time. The percentage increases do not track in U.S. dollar figures because of variations in the exchange rate.
China's defense budget has for years been the world's second largest, although still lagging far behind the U.S.
Fu also said the percentage of GDP China spends on defense is below the 2 percent the U.S. calls on NATO allies to spend.
"The gap in capabilities with the U.S. is enormous, but China's military development and construction will continue in keeping with our need to defend our national sovereignty and security," Fu said.