Blantyre - Malawi banned all exports of Malawi's staple maize crop and fertiliser on Monday in a bid to avert famine in the drought-stricken southern African country.
President Bingu wa Mutharika urged Malawians to contribute at least 10 percent of their earnings to a fund to help feed the needy.
Traders have been buying up cheap Malawi grain and fertiliser to sell in neighbouring Zambia and Tanzania, where they command higher prices.
"From today our borders are sealed," Wa Mutharika said at the launch of a new fertiliser company. "We have to feed ourselves first."
He urged residents to keep an eye on trucks crossing the border and report any suspicious exports to local authorities.
Wa Mutharika also contributed one million Malawi Kwacha ($8 300) to the food drive, saying the country should show the world it can feed itself before turning to donors for help.
Malawi needs more than two million metric tons of maize each year to feed its 11 million people. Drought has reduced this year's harvest to 1.3-million metric tons.
A recent government assessment found 4.2 million people were in need of food.
The United Nations World Food Programme is targeting 1.5 million of the neediest, some of whom have resorted to eating wild tubers to survive. - Sapa-AP