Soaring cabbage prices caused by heavy snowfall and a longer-than-expected cold spell are threatening supplies of kimchi, South Korea's beloved national dish, officials said Tuesday.

The spicy side dish, made by mixing pickled cabbage, radish and cucumbers with spices and condiments, has inspired its own museum in Seoul and was even blasted into space with the country's first astronaut in 2008.

An upsurge in the price of ingredients is driving some housewives to break their ritual of making kimchi at home and turn to online shopping malls selling packaged kimchi at fixed prices.

Many restaurants are offering reduced portions of kimchi or alternative vegetables.

A head of cabbage was priced at over 6,000 won (5.5 dollars) on Monday, compared to less than 4,000 won a year earlier, said the state-run Korea Agro-Fisheries Trade Corp, which controls the distribution of agriculture and fishery products.

"Normally at this time of the year the price of cabbage is going up but this year the price has inflated unusually due to cold weathers and snow," a corporation official told AFP on condition of anonymity.

The price of cabbage has soared 191 percent so far this year.

"We have yet to see whether the price will stabilise" to an annual average 2,000 won, said another corporation official.

Kimchi supplies will be in "big trouble" if the current price continues or farmers delay the shipment of greenhouse cabbage further, he said, adding stocks of field cabbage have nearly run out.

"Sales of kimchi have doubled this year, compared to a year earlier," said Lee Seung-Je, a spokesman for online shopping mall GS Shop spokesman.

Lee said his company has been able to maintain a low price due to long-term contracts with kimchi companies.

Poor harvests have also driven up the price of other vegetables and the cost of living.

Consumer prices in March rose 2.3 percent from a year ago, led by soaring prices in vegetables and fishery products, according to Statistics Korea.

South Korea is estimated to consume about two million tons of kimchi a year. It imported about 142,000 tons of cheap kimchi from China last year.