The US took a major step toward ending one of the quirkiest holdovers from the Cold War era: the effective ban on travel by most US nationals to communist Cuba next door.

A group of US senators introduced legislation that would let most Americans travel to Cuba.

"We believe engagement with trade and travel is the best way to promote democracy" in Cuba, said Democrat Bryan Dorgan, one of the measure's sponsors.

For decades US citizens have been barred from spending money on the island, an effective travel ban.

Only journalists, people on educational or sports exchanges have been allowed to travel to Cuba - the only country in the Americas with a one-party communist regime.

Those Americans who do dare defy US sanctions regulations to give Cuba a go face major fines.

"We have been trying the same thing" for decades, said Republican Michael Enzi, a measure co-sponsor, "and our strategy has not worked. It is time for a different policy."

Washington imposed a full economic embargo, including travel restrictions, on Cuba in 1962 with the goal of crippling Fidel Castro's regime.

Experts have predicted scrapping travel restrictions could prompt a tidal wave of visitors from a country of 300 million just 144 kilometres away from Cuba, with an estimated one to five million Americans visiting each year.

Cuba, with more than 11 million people, recently has welcomed a total of more than two million tourists a year, mostly Europeans and Canadians.

But following the US senators' move, officials in Havana said they have made no special preparations for a possible influx of US tourists.

"We will continue with our working projections," said Deputy Tourism Minister Maria Elena Lopez.