North Korea has said it will not agree to further nuclear talks unless South Korea's admission about secret nuclear experiments was "fully probed".
The six-nation talks were due to discuss N Korea's nuclear facilities
The North's official KCNA news agency said Seoul's recent disclosure had "thrown great hurdles" in the way of further multi-party talks.
Seoul has admitted its scientists did conduct small-scale secret trials.
The admission dampened hopes that any progress would be made soon in ridding the North of its nuclear capabilities.
"[North Korea] clarified its stand that it can never sit at the table to negotiate its nuclear weapon programme unless [the] truth about the secret nuclear experiments in South Korea is fully probed," KCNA quoted a North Korean foreign ministry spokesman on Thursday.
A new round of talks - between China, the two Koreas, the US, Japan and Russia - was due to have taken place later this month.
Three previous rounds have made little headway, but analysts still see the multi-party discussions as the best chance of resolving the standoff over Pyongyang's nuclear ambitions.
There has been recent speculation that North Korea wanted to delay further discussions until it knew the outcome of the US presidential election.
But a foreign ministry spokesman told KCNA that the North "does not care" who becomes the next US President.
The BBC's Charles Scanlon, in Seoul, says that South Korea's disclosure appears to have strengthened the North's position, as it seeks economic and diplomatic compansation for any nuclear concessions.
South Korea stunned the region on 2 September when it revealed that it had fallen foul of international nuclear accords.
A small number of South Korean scientists had conducted secret tests to produce 0.2g of enriched uranium in 2000, the government admitted.
It said the experiments were not authorised by the government, and were conducted for South Korea's civilian nuclear power industry.
Later it also admitted that a small amount of plutonium - a key ingredient in nuclear bombs - had been extracted in secret research conducted in the early 1980s.
The revelation is deeply embarrassing, both to South Korea and its ally the US, which has already chastised Seoul for the secret experiments.
North Korea said last weekend that the news of South Korea's tests had made it even more determined not to abandon its own weapons programme.