The Bolivian leader has good relations with Fidel Castro, in Cuba, and Hugo Chavez, in Venezuela, who are both critics of George Bush's government in the US. However, Morales is not opposed to developing ties with the United States, Alex Contreras said on Saturday.
Morales, who will also fly to Europe this week, would have gone to Washington as well if he had been asked, Contreras said. His close ties with his Latin peers "do not aim at an axis of evil; rather, to an axis of good", the spokesman said.
"The president-elect is prepared to talk [to US officials] as long as diplomatic conditions are different from what they have been before," Contreras said.
If that does not happen, "unfortunately, relations with the United States can deteriorate badly", he said.
Officials in Washington have been fretting about the relationship between Presidents Morales, Chavez and Castro, which they fear as part of a Latin-American tilt to the left.
They are also worried about Morales' opposition to US-led efforts to eradicate coca cultivation in his country. Coca has traditional uses among Indians, not just the cocaine production that the US says it wants to stop.
Morales, a coca grower and former street protest leader who was elected president last month, says he supports coca growing but opposes cocaine trafficking.
Morales plans to spend only about six hours before starting a tour of Spain, France and Belgium before moving on to South Africa, China and Brazil, Contreras said.
Free eye operations
He said Chavez had already offered aid to the Bolivian government, including a programme to provide identity documents to people in Bolivia's rural areas. Chavez "has offered to make available to Bolivia all the technology and human resources for such a plan", Contreras said.
Morales, who takes office on 22 January, was a frequent visitor of Castro and Chavez before being elected.
During his visit to Havana, Castro called his election victory historic, and the two leaders said that co-operation between their countries would increase.
Cuba also plans to offer free eye operations to up to 50,000 poor Bolivians needing them.