Thousands took to the streets across Cuba to celebrate former leader Fidel Castro's 90th birthday.

Cubans partied along Havanas's Malecon seafront into the early hours of Saturday to honour 'El Comandante'.

On the strike of midnight, a live band, accompanied by fireworks, played Happy Birthday in honour of the iconic revolutionary on the Anti-imperialist Tribune, a plaza located outside the newly-opened U.S. embassy.

"This is the best gift we can give him, this party," said dancer Leydis Campos, 25.

"To 90 years past, and to 90 more!" she said.

Tributes to the retired leader included the longest cigar measuring 90 metres.

Castro, who rarely makes public appearances now, led the South American country's 1959 revolution and built a Communist-run state on the United States doorstep.

Fidel handed over the reins of power in 2008 to his younger brother Raul due to an intestinal ailment that nearly killed him, although he retained the title 'Historic Leader'.

Castro was not at the celebrations in his honour, but may be meeting ally Venezuelan President Nicolas Madura later today.