A drought struck the sugarcane crop in the northern provinces and in the Central Highlands between December 2004 and June this year, followed by heavy rains and storms between July and October.
"The shortage is inevitable after natural disasters," Le Van Tam, chairman of the Vietnam Sugar and Sugarcane Association, told Reuters.
The association has asked the Agriculture and the Trade Ministries to allow the importation of the sugar, which could come from Thailand, Australia or Brazil, he said.
A shortage of sugarcane leading to slower-than-expected production of refined sugar has driven retail prices in Ho Chi Minh City to a 10-year high of between 11,700-12,000 dong ($0.74-$0.75) per kg.
The price was expected to rise to 15,000 dong per kg ahead of the Lunar New Year festival later this month on demand from candy makers.
Speculative buying and traders covering short positions pushed London white sugar futures higher on Thursday with March moving to a contract high of $353 a tonne, the highest in more than nine years, before closing at $351.6.
Six Mekong Delta sugar plants in southern Vietnam have not been able to start production because of a lack of supply, Tam said. State-run media has said buying agents there have been scrambling to persuade growers to harvest cane early.
A government report said sugarcane output fell 5.9 percent this year to 14.7 million tonnes from last year as the sugarcane acreage was cut by 6.9 percent to 266,400 hectares this year. "Extended rains have slowed the sugarcane's maturing process and also reduced the sugar content," Tam said from the northern province of Thanh Hoa, an area hit by a typhoon in late October.
The delayed harvest prevented many refiners from starting crushing until early this month, a month later than usual, while stocks have thinned.
The association forecast Vietnam's sugar demand from November to January at 100,000 tonnes to 130,000 tonnes a month, while domestic production could supply only 90,000 tonnes a month.
"The heated demand will decrease from February, after Tet and when the production is at a peak," Tam said, referring to the country's New Year holiday.
Vietnam's sugar productiion slumped 18.5 percenty this year to 1.1 million tonnes from last year, government statistics show.
The shortage has triggered smuggling of Thai sugar across the border from Cambodia into southern Vietnam where it costs 1,500 to 2,000 dong per kg less than Vietnamese sugar, state media reported.