Chavez accused the government of President Alvaro Uribe of acting "irresponsibly," saying there is no evidence the Swedish-made anti-tank rocket launchers that Colombia says its military seized came from Venezuela.
The socialist leader threatened to break off all diplomatic relations and seize control of Colombian-owned businesses "if there's one more accusation against Venezuela." Venezuela would also halt all trade agreements with Uribe's government and find new suppliers to replace imports from Colombia, he said.
The two countries share some $6 billion in annual trade. Among goods imported from Colombia are milk and other food items that periodically become scarce in Venezuela due to government-imposed price controls.
"We can get them from any other country," Chavez said.
His warning to Colombia stems from Bogota's announcement last week that anti-tank rocket launchers sold to Venezuela by Sweden during the 1980s were obtained by Colombia's main rebel group, the leftist Revolutionary Armed Forces of Colombia, or FARC. Sweden confirmed the weapons originally were sold to Venezuela's military.
Colombian officials have long alleged that Chavez's government has aided the FARC - a charge that Chavez denies.
Relations between the two South American nations have been rocky in recent years. Tensions hit their low point in 2007 after Colombia attacked a FARC camp in Ecuador. Chavez responded by briefly dispatching troops to the 1,400-mile (2,300-kilometer) border with Colombia and temporarily pulling out his ambassador in Bogota.
The current fight comes amid Venezuelan criticism of Colombia's decision to forge stronger military ties with the United States.
Chavez, who has sought to use Venezuelan oil wealth to counter U.S. influence in the region, has called a pact being negotiated to let U.S. forces use three airfields and two navy bases in Colombia a threat to Venezuela.
Colombian officials say Venezuela should not be concerned, saying the U.S. forces will be helping fight drug trafficking. Colombia says the number of U.S. service personnel and civilian military contractors will not exceed the 1,400 mandated by the U.S. Congress.