Duterte told reporters he preferred to engage China in a diplomatic dialogue rather than take a more aggressive stance that could anger Chinese officials into calling off possible talks.
Former President Fidel Ramos, a key political backer of Duterte, met Chinese intermediaries recently to pave the way for the talks, to be held in Beijing.
An international arbitration tribunal ruled last month that China's massive territorial claims in the South China Sea based on historical grounds were invalid under a 1982 UN treaty, in a major setback for Beijing, which has ignored the decision.
"It's better to continually engage China in a diplomatic dialogue rather than anger whoever the officials there and they cut completely," Duterte said, adding that possible talks on maritime and security issues would be undermined if ties are strained.
"China should be hearing us out now, about time that you lift the bans on tourists and allow the Filipinos to fish there," Duterte said, referring to past Chinese restrictions on tourism and on access for Filipino fishermen to Chinese-controlled Scarborough Shoal, which Beijing seized in 2012.