Some 300,000 flag-waving Cubans marched past a reviewing stand in Havana's Revolution Square in salute to the commandant they had hoped would make his first public appearance since surgery four months ago.

Castro's absence at the event marking his 80th birthday and the 50th anniversary of the start of the revolution that put him in power accelerated speculation that he may be fading into history after 47 years in control.

"It means he will not return to power, that's for sure. Otherwise he would have made it," said a European diplomat who attended the parade but asked not to be identified.

The biggest military parade in Cuba since 1986 capped five days of celebrations that felt more like a farewell than a birthday party and included conferences on Castro's place in history. The events were attended by left-wing politicians and intellectuals from dozens of countries.

Castro had emergency intestinal surgery in late July that forced him to temporarily turn over power to his brother Raul Castro. He has appeared feeble in the few photos and videos released by the government.

Raul Castro, Cuba's acting president and defence minister, led the parade, but said nothing about his brother's condition or absence in a speech.

He quoted from a past Fidel speech, praised the Cuban people for their "maturity" the past four months and at the end shouted "Viva Fidel."