President Raul Castro of Cuba says the future of the island's 1959 revolution is at stake if proposed economic reforms are not adopted.
The government is about to begin the first major overhaul of Cuba's state-run system.
It wants to expand the private sector and reduce the role of the state.
"We are playing with the life of the revolution," President Castro told parliament in a two hour speech.
The BBC reports the island's Soviet-style command economy is in deep financial trouble and the government can no longer afford the massive subsidies that make up for low wages.
Half a million state workers are due to lose their jobs, while restrictions are being eased on people who want to become self-employed or set up small businesses.
President Castro said the changes would not turn Cuba capitalist.
The aim, he said, was to strengthen the socialist system created by Fidel Castro after the revolution in 1959.