Japan's Trade Minister Shoichi Nakagawa told US Agriculture Secretary Ann Veneman Washington would have to adopt a new testing regime before Tokyo lifted its ban on US beef.
"Even if we re-open trade, if we cannot win the trust of consumers, the consumption of US beef will plummet," Nakagawa said in Washington on Wednesday after talks with Veneman.
"Rushing to a conclusion will only bring failure," he said.
During their talks, Veneman told Nakagawa the US had banned the sale of high risk cow parts such as brain and spinal cord in order to maintain safety.
Japan is the largest market for US beef and was the first to ban imports after mad cow disease was discovered.
Japan was the only Asian country to discover mad cow disease among its herd in September 2001.
Since then, nine Japanese cows have been confirmed to have had the disease.
No lifting of ban
Meanwhile, Japan's Agriculture Ministry on Thursday denied a report it was considering ending the ban if the beef was inspected and proven to be free of mad cow disease.
The Nihon Keizai economic daily reported that Tokyo was considering accepting US beef determined to be BSE-free by firms certified by the US government, but an official said no such study was underway.
The mad cow scare has seen
people change their eating habits
"There has been no specific proposal from the US government," ministry official Toshiro Kawashima said. The report "is not true," he added.
Kawashima said Japan would wait for a proposal from the US before making a decision on its ban.
On Thursday, Japan sent a five-member fact-finding mission to the US and Canada in advance of deliberations on whether Japan would lift its ban.
Japan imported 333,272 tonnes of US beef and beef products in 2002, accounting for about one-third of the country's market, according to official data.
Since the import ban was announced, restaurants have announced menu changes, US beef-related companies have seen their share prices plummet and Japan has begun studying increasing imports from Australia and New Zealand.