Japan is preparing permanent limits on some agricultural imports from China, a move that could push the trade dispute between the two countries before the World Trade Organization.

Japanese Trade Minister Takeo Hiranuma says the prime minister has told him to begin preparing long-term restrictions on imports of Chinese leeks, shiitake mushrooms and rushes used to make traditional floor mats. Speaking at a news conference Friday, Mr. Hiranuma says the plans must be ready soon. "Given that there is not much time left, we have to step things up in order to make a decision," Mr. Hiranuma said.

Japan imposed what it called temporary safeguard import curbs in April on those products, saying the limits were needed to protect Japanese farmers. The temporary curbs ran out last week.

The two governments have met several times to discuss the issue but have not found a solution. In another news conference Friday, Japanese Agriculture Minister Tsutomo Takabe said he hopes a voluntary cutback in shipments by Chinese exporters would be a way to resolve the old dispute.

Last month, a Chinese trade association ordered exporters of stone leeks to cut shipments to Japan.

Earlier, the government in Beijing took a hard line. In June, it retaliated for the Japanese import ban by slapping 100 percent tariffs on Japanese cellular phones, automobiles and air conditioners.

Under the rules of the World Trade Organization, which China joined this month, Tokyo will have to present evidence to justify its sanctions. The case could be the first trade dispute involving China to go before the WTO's dispute resolution body.