Prime Minister Nguyen Xuan Phuc has told the ministries of trade, finance and agriculture to take stock of rice supplies and submit a report on supplies and exports by Saturday, according to the statement.
"While waiting for the report from the working group, the signing of all new rice export contracts will be suspended, and those contracts that have already been signed will be dealt with after the report is available," the government said.
The ban would be in force until after the report was submitted on March 28, it said.
On Tuesday, a government food official told Reuters Vietnam would continue rice exports, despite reports by state media and customs officials that a government ban on exports had been in effect.
The mixed messages have created confusion in the domestic market, rice traders told Reuters.
"We've been worried and confused by the signals from the authorities and have stopped purchasing rice from farmers from Tuesday," a trader based in the Mekong Delta province of An Giang said.
The prime minister this month vowed to protect food security during the coronavirus outbreak, state media reported.
A European rice trader said Vietnam's export ban was being carefully watched.
"This move by Vietnam is causing a lot of attention in the international market,? the European trader said.
"If food exporting countries start limiting supplies to secure their own food security this would be of very great concern.?
Vietnam has reported 134 cases of the coronavirus but no deaths, according to the health ministry. More than 1,500 suspected cases are in quarantine and monitored.
Vietnam's rice exports rose 4.2% last year to 6.37 million tonnes. The largest buyers of its rice include the Philippines, China and African countries.
By Khanh Vu
