Diplomats involved in the stalled six-party talks are making the rounds in Beijing and Washington to find ways to convince Pyongyang to stop development of nuclear weapons, Yonhap news service reported.
Members of South Korea's Parliament expressed doubt the talks would succeed.
"I am concerned that this seems to be a revival of past failures," said Chung Mong-jun, a member of the ruling Saenuri Party.
He accused China of "veering away from its previous stance that the six-way forum will not reopen until some requirements are met," adding Washington's attempt to restart the talks appears to be an admission "it has no more power or will to pressure North Korea any further."
"Resuming the negotiations, even without North Korea showing willingness to discard nuclear programs, means giving the country indulgence," he said.
Choung Byoung-gug, another Saenuri lawmaker, noted North Korea had resumed operation of a 5-megawatt nuclear reactor, which he said indicated the country's lack of interest in restraining its nuclear program.
He added North Korea "will go its own way even after the talks are resumed."
The six-party talks involve negotiators from North and South Korea, China, the United States, Japan and Russia.