The poor state of Vietnam's roads and other infrastructure poses the key obstacle faced by foreign investors as the communist country battles to boost its exports, business leaders said Tuesday.

Almost 96 percent of foreign trading firms rated the country's infrastructure as "bad" or "very bad" according to a survey presented to the Vietnam Business Forum.

Unless the government works to remedy the problem, "the country's infrastructure status will act as a deterrent to foreign investment and the enhancement of Vietnam's export sector," the survey said.

The figure is "staggering", Tony Foster, who heads a forum sub-committee which includes multinational corporations, told the gathering of government officials, foreign diplomats, businessmen and aid agencies.

Vietnam has already seen a precipitous drop in foreign direct investment this year. At about 19.7 billion dollars from January to November, the total was barely a quarter of the amount registered over the same period of 2008.