The US is looking to open an embassy in Cuba within a few weeks, as the two Cold War enemies seek to normalise diplomatic relations after decades of estrangement and embargoes.

President Barack Obama hopes to have a Washington envoy to Havana before the Summit of the Americas that is to be held in Panama City in mid-April.

"My hope is that we will be able to open an embassy, and that some of the initial groundwork will have been laid [before the Summit]," he told Reuters

US-Cuban relations experienced an historic breakthrough in December with the release of American contractor Alan Gross, jailed for five years in Cuba, in exchange of three Cubans convicted of espionage in Florida in 2011.

The deal saw the old adversaries agree to restore diplomatic ties after five decades of acrimony.

Obama said the opening of an embassy in Havana is one the first steps towards more amicable relationships between the two countries with an overhaul of the Kennedy-era Cuban embargo on the horizon.

"Keep in mind that our expectation has never been that we would achieve full normal relations immediately. There's a lot of work that still has to be done".

The president said he is confident the dramatic shift in US policy towards its Caribbean neighbour will bring about positive change in Cuba.

"The very fact that, since our announcement, the Cuban government has begun to discuss ways in which they are going to reorganize their economy to accommodate for possible foreign investment, that's already forcing a series of changes that promises to open up more opportunities for entrepreneurs, more transparency in terms of what's happening in their economy," he told Reuters,

Obama added that such transformation will in turn help "create more space for freedom for the Cuban people".