Pakistan's daily Dawn on Tuesday cited a report by the Financial Times as saying that three people with knowledge of the talks told the Times that Beijing had been in direct contact with militants in Balochistan, where many of the CPEC-related schemes were located.
"The Chinese have quietly made a lot of progress," one Pakistani official said. "Even though separatists occasionally try to carry out the odd attack, they are not making a forceful push."
The CPEC links China's Kashgar in Xinjiang province with Pakistan's Gwadar port in Balochistan through a network of roads, railways and highways.
India strongly objects to the route of the corridor, which goes through Pakistan-occupied Kashmir.
The Times reported that the Pakistani officials welcomed the talks between Baloch rebels and Chinese envoys, even without knowing what all had been discussed.
"Ultimately, if there's peace in Balochistan, that will benefit both of us," said one official in Islamabad.
Another said that the recent decision by the US to suspend security assistance to Pakistan had convinced many in Islamabad that China was "a more genuine partner".
"(The Chinese) are here to stay and help Pakistan, unlike the Americans, who cannot be trusted," the official said.
Chinese officials did not comment on the talks, though the Chinese ambassador to Islamabad said in a recent interview with the BBC that militants in Balochistan were no longer a threat to the economic corridor.
One provincial tribal leader said many young men had been persuaded to lay down their weapons by the promise of financial benefits.
"Today, young men are not getting attracted to join the insurgents as they did some 10 years ago," he said. "Many people see prosperity" as a result of the CPEC, he added.