China's slowdown may deepen as policymakers unwind the excesses of a record credit boom while gradually stepping up stimulus, leaving 2012 growth the weakest in 13 years, Pacific Investment Management Co said.

"The economy is unlikely to bottom until the third quarter," Ramin Toloui, Pimco's global co-head of emerging markets portfolio management in Singapore, said in e-mailed comments.

"Policymakers will progressively turn the dial toward more stimulus, but not in the aggressive manner of 2009", restrained by the goal of tempering the credit-fueled property market, he said.