Toyota's plant in Venezuela has more than 2,000 workers
Venezuela's President Hugo Chavez has told car companies they must share their technology with local businesses or leave the country.
Mr Chavez gave the ultimatum to Toyota, Ford, General Motors and Fiat during a public address.
If the demand isn't met, he said: "I invite you to pack up your belongings and leave. I'll bring in the Russians, the Belorusians, the Chinese."
Venezuela has nationalised most of the oil, metal and coffee industries.
Mr Chavez attacked Toyota in particular, saying it was not producing enough four-wheel drive vehicles, which are used for public transport, and ordered an investigation.
So far, the carmakers have not responded.
Last year, car plants in Venezuela produced 135,042 cars and trucks.
Currency controls in Venezuela mean the industry is struggling to get enough money to import parts and pay off debts.