"People in the US administration suspect China is not doing much" in order to solve the standoff, the minister said in a televised debate on public broadcaster NHK.

"It is important that China... tackle this issue seriously and exert a greater influence, though I believe they have made efforts in the past," he said.

China, North Korea's closest ally, urged Japan and North Korea last week not to do anything to complicate the resumption of international multi-party nuclear talks, cautioning Tokyo against imposing sanctions on Pyongyang.

North Korea says it would regard any sanctions imposed on it by Japan as a declaration of war and would hit back with an "effective physical" response.

Many Japanese support sanctions after North Korea provided Tokyo with the wrong ashes to support its claim that two Japanese it kidnapped during the Cold War had since died.

Machimura told NHK that "there has been no sign from them that they would agree" to the resumption of talks, also involving South Korea, China, Russia and the United States.

But the Japanese minister warned the nuclear issue would not be allowed to drag on for many years.

If the issue prolongs further, "it would become inevitable that the issue would go to the Security Council and that the United Nations will take severe measures, including sanctions," he said.

"They should recognise the time given to North Korea is actually not so long," he said, while adding Japan did not have specific plans to bring the nuclear issue to the United Nations at present.

Three rounds of six-way talks to end North Korea's nuclear ambitions have taken place since the standoff erupted in October 2002.

North Korea boycotted a fourth round of the talks scheduled for Beijing in September, citing Washington's "hostile policy" toward the communist state.

Citing outgoing US deputy secretary of state Richard Armitage, a ruling-party lawmaker, said Washington would support Japan if it imposed sanctions.

"Mr. Armitage clearly told me... the true intention of the United States is that they support Japanese economic sanctions" no matter whether they would be mild or severe, Takeo Hiranuma said.

Hiranuma, chairman of a parliamentarian group for kidnap victims pushing for sanctions against Pyongyang, made the remark in a interview on the private Asahi network after meeting US officials.

It contradicted a briefing last week by Yuriko Koike, the state minister in charge of frontier territories who said Armitage and Michael Green, the Asia chief of the US National Security Council, had voiced caution to sanctions.

As for a Japanese newspaper report Saturday that US President George W. Bush would not aim to topple the regime of Kim Jong-Il in his second term, Hiranuma said he had the same impression from meetings with US officials.

"I got the impression that they would not take tough measures that would ruin the window (of dialogue) completely as they have six-party talks with Kim Jong-Il for now," he said.

In a new bid to increase pressure on North Korea, Japan would soon start work to prepare a Japanese version of US law aimed at improving human rights in North Korea, the Nihon Keizai Shimbun said Sunday.

The Japanese legislation would ban aid to North Korea except for humanitarian purposes until human rights issues there improve including the problem of Japanese kidnapped by the North's agents, the economic daily said.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.