In 2004 Nicaragua destroyed 1,000 missiles out of the 2,000 donated by the Soviet Union when Ortega's government was fighting a civil war against US-backed rebels in the 1980s.
The missiles were destroyed partly at the request of the US which feared that the shoulder-fired Sam-7 missiles could be used to attack airliners.
Congress is now considering a proposal by Enrique Bolanos, the former Nicaraguan president, to destroy a further 650 of the missiles, keeping the remaining 400 for self-defence purposes.
Ortega objects to plan
Ortega however told parliament that the proposal was unacceptable at at time when neighbouring Honduras was adding to its fleet of military aircraft.
"Even if they aren't upgrading it, the fact that Honduras has an air force, and El Salvador too, and we do not - that explains why Nicaragua has the missiles," Ortega told parliament.
"I want to raise the attention of deputies in the National Assembly that ... independently of our political differences, we have to watch over the sovereignty of our country."
"If on the one hand they are going to renovate the Honduran air force, an air force of war, a military air force, and on the other hand they are going to ask us to destroy the rockets, it would be absurd, inconceivable."
Honduras, which has the biggest air force in Central America, said last week the United States had offered it around 10 small reconnaissance aircraft.
It said they would be for spotting illegal logging or drug smugglers rather than combat.
Nicaragua's military has Soviet-made helicopters but no airplanes.