The UN security council was expected to vote on Friday on the resolution, but a draft has now been softened and rules out military force against North Korea, but includes proposals for economic and weapons sanctions. A vote is expected on Saturday.
Meanwhile, Japan's cabinet has voted to press ahead with its own sanctions, banning imports and blocking North Korean ships from entering its ports.
Condoleezza Rice, the US secretary of state, speaking after talks between George Bush, the US president, and a senior Chinese envoy at the White House on Thursday, played down expectations of a Friday vote.
"I don't know that it will be tomorrow, but I think it will be soon," she said.
A US official had said that in the talks between Bush and Tang Jiaxuan, the former Chinese foreign minister, there was agreement that "strong measures" were needed against North Korea, which has had strong political and economic support from Beijing.
JD Crouch, a White House deputy national security adviser, had said there was broad understanding with China over the way forward but acknowledged the "possibility for some differences" over the specifics of the resolution.
"I think that the council should try to respond to a nuclear test within the same week that the test occurred"
US ambassador to the UN
The announcement from Pyongyang on Monday that it had carried out a nuclear weapons test prompted stiff Chinese and Russian condemnation that encouraged US hopes for a united response from the big powers at the UN.
John Bolton, the US ambassador to the UN, who formally introduced a sanctions resolution to the security council, said: "I think that the council should try to respond to a nuclear test within the same week that the test occurred."
But Beijing seemed to back away from some key points in the resolution and Wang Guangya, its UN ambassador, suggested the vote would be next week. Russia's ambassador, when asked about a Friday vote, said: "I don't think so."
Wang criticised about 10 points in the draft, such as the scope of financial sanctions and travel restrictions, participants in a closed-door council meeting reported.
Wang also objected to a controversial provision in the US draft, co-sponsored by security council members Japan, Britain, France and Slovakia, that authorises the inspection of cargo going in and out of North Korea to detect ballistic missiles or nuclear materials.
The resolution includes an arms embargo, a ban on any transfer or development of weapons of mass destruction as well as a ban on the sale of luxury goods to North Korea.
The leaders of China and South Korea will meet in Beijing on Friday to seek a response to Pyongyang's nuclear defiance.