President Barack Obama is poised to offer an olive branch to Cuba in an effort to repair the US's tattered reputation in Latin America.

The White House has moved to ease some travel and trade restrictions as a cautious first step towards better ties with Havana, raising hopes of an eventual lifting of the four-decade-old economic embargo. Several Bush-era controls are expected to be relaxed in the run-up to next month's Summit of the Americas in Trinidad and Tobago to gild the president's regional debut and signal a new era of "Yankee" cooperation.

The administration has moved to ease draconian travel controls and lift limits on cash remittances that Cuban-Americans can send to the island, a lifeline for hundreds of thousands of families.

"The effect on ordinary Cubans will be fairly significant. It will improve things and be very welcome," said a western diplomat in Havana. The changes would reverse hardline Bush policies but not fundamentally alter relations between the superpower and the island, he added. "It just takes us back to the 1990s."

The provisions are contained in a $410bn (£290bn) spending bill due to be voted on this week. The legislation would allow Americans with immediate family in Cuba to visit annually, instead of once every three years, and broaden the definition of immediate family. It would also drop a requirement that Havana pay cash in advance for US food imports.

"There is a strong likelihood that Obama will announce policy changes prior to the summit," said Daniel Erikson, director of Caribbean programmes at the Inter-American Dialogue and author of The Cuba Wars. "Loosening travel restrictions would be the easy thing to do and defuse tensions at the summit."

Latin America, once considered Washington's "backyard", has become newly assertive and ended the Castro government's pariah status. The presidents of Brazil, Chile, Dominican Republic, Ecuador and Guatemala have recently visited Havana to deepen economic and political ties. Brazil's president, Luiz Inácio Lula da Silva, is expected to tell Obama on a White House visit this week that the region views the US embargo as anachronistic and vindictive. Easing it would help mend Washington's strained relations with the "pink tide" of leftist governments.

Obama's proposed Cuba measures would only partly thaw a policy frozen since John F Kennedy tried to isolate the communist state across the Florida Straits. "It would signal new pragmatism, but you would still have the embargo, which is the centrepiece of US policy," said Erikson.

Wayne Smith at the Centre for International Policy, Washington DC, said: "I think that the Obama administration will go ahead and lift restrictions on travel of Cuban Americans and remittance to their families. He may also lift restrictions on academic travel.

"There are some things that could be done very easily - for example it's about time we took Cuba off the terrorist list. It's the beginning of the end of the policies we have had towards Cuba for 50 years. It's achieved nothing, it's an embarrassment."

Wayne Smith, a former head of the US Interest Section in Havana, famously said Cuba had the same effect on American administrations as the full moon had on werewolves.

Cuban exiles in Florida, a crucial voting bloc in a swing state, sustained a hardline US policy towards Havana even as the cold war ended and the US traded with other undemocratic nations with much worse human rights records.

To Washington's chagrin, the economic stranglehold did not topple Fidel Castro. When Soviet Union subsidies evaporated, the "maximum leader" implemented savage austerity, opened the island to tourism and found a new sponsor in Venezuela's petrol-rich president, Hugo Chávez.

When Fidel fell ill in 2006, power transferred seamlessly to his brother Raúl. He cemented his authority last week with a cabinet reshuffle that replaced "Fidelistas" with "Raúlistas" from the military.

Recognising Castro continuity, and aghast at European and Asian competitors getting a free hand, US corporate interests are impatient to do business with Cuba. Oil companies want to drill offshore, farmers to export more rice, vegetables and meat, construction firms to build infrastructure projects.

Young Cuban exiles in Florida, less radical than their parents, have advocated ending the policy of isolation. As a senator, Obama opposed the embargo, but as a presidential candidate he supported it - and simultaneously promised engagement with Havana.

A handful of hardline anti-Castro Republican and Democrat members of Congress have threatened to derail the $410bn spending bill unless the Cuba provisions are removed, but most analysts think the legislation will survive.

Compared to intractable challenges in Afghanistan, Pakistan and the Middle East, the opportunity for quick progress on Cuba has been called the "low-hanging fruit" of US foreign policy.

That Obama has moved so cautiously has frustrated many reformers. But after decades of freeze, even a slight thaw is welcome, and there is speculation that more will follow.

Old enemies

President Kennedy imposed an economic and trade embargo on Cuba on 7 February 1962 after Fidel Castro's government expropriated US property on the island. Known by Cubans as el bloqueo, the blockade, elements have been toughened and relaxed under succeeding US presidents. Exceptions have been made for food and medicine exports. George Bush added restrictions on travel and remittances.

The sanctions regime

• No Cuban products or raw materials may enter the US

• US companies and foreign subsidiaries banned from trade with Cuba

• Cuba must pay cash up front when importing US food

• Ships which dock in Cuba may not dock in the US for six months

• US citizens banned from spending money or receiving gifts in Cuba without special permission, in effect a travel ban

• Americans with family on the island limited to one visit every three years.