A Japanese politician has called the latest US threat to punish Tokyo over its ban on US beef "preposterous," according to an AFP report carried by Channel News Asia

A bipartisan group of the US House of Representatives submitted a resolution Thursday demanding Japan open up its market to US beef, following similar calls in the senate for trade sanctions unless Tokyo moves swiftly.

Tsutomu Takebe, secretary general of Japan's ruling Liberal Democratic Party, denounced the latest US moves. "It is preposterous. If they want to export to Japan, they obviously have to abide by the Japanese standards," said Takebe, a former farm minister.

Japan stopped buying US beef in December 2003 after a cow slaughtered in Washington state was found to have bovine spongiform encephalopathy (BSE) or mad cow disease, linked to a fatal brain condition in humans.

Japan, which was the biggest market for US beef until the ban, has agreed in principle to restart the multi-billion dollar trade.

However, the country's Food Safety Commission is trying to decide how best to test animals for slaughter, which had led to delays.

"The outcome will come out soon. But unless we have the (safety commission's) conclusion, we cannot move forward," chief cabinet secretary Hiroyuki Hosoda, a government spokesman, said Friday.

The latest US threat came on the same day that its senate passed a resolution opposing a resumption of beef imports from Canada due to mad cow fears.

Japan has screened every cow slaughtered for consumption since September 2001 when it became the only Asian nation to report mad cow disease among its domestic herds.

After intense US pressure, Japan said in October it would exempt US cows aged 20 months or younger from screening tests if high risk parts such as brains and spinal cords were removed.

The main dispute remains over how to verify the age of the cattle, with Japanese experts saying they did not have enough data to accept the method recommended by the United States.

On Tuesday, US agriculture secretary Mike Johanns accused Japan of having a "plodding regulatory process" and said further delays on ending the beef ban "could further complicate relations between the United States and Japan."