Cuban President Raul Castro has said term limits should be introduced for top political positions on the island, including the presidency.

He was speaking at the start of the first congress of Cuba's ruling Communist Party in 14 years.

The term limits proposal is unprecedented under Cuban Communism.

He said the party leadership was in need of renewal and should subject itself to severe self-criticism, and that key positions should be limited to two five-year terms from now on.

Raul Castro, 79, took over from his brother Fidel in 2008. Between them they have ruled Cuba for the past 52 years.

The four-day party congress is expected to see 1,000 delegates back all or part of a package of nearly 300 reforms.

Fidel Castro, who has led the party since its founding in 1965, announced three weeks ago he had resigned the party leadership when he first took ill. He is widely expected to pass that mantle to Raul officially.

The congress will elect a new 100-member Central Committee, as well as the more elite 19-member Politburo and 10-member Secretariat.

The government has said the congress will formally enshrine many economic reforms the government has adopted over the past year.