On Monday Cuba announced jail sentences ranging from three-and-a-half to five years for the country's four best-known dissidents, convicted of inciting sedition.
Aznar also criticised tough new Cuban legislation aimed at quashing subversion in the former Spanish colony.
``It is legislation that in the democratic atmosphere of the end of the 20th century is incomprehensible,'' he said at joint news conference with Colombian President Andres Pastrana.
Spain's conservative prime minister said the punishment meted out to the four dissidents was overly harsh. ``They are sentences that without doubt can and must be seen as a profound and regrettable step backwards,'' he said.
Aznar said whether or not King Juan Carlos and Queen Sofia went ahead with a planned visit to Cuba later this year would depend on conditions being right on the island.
``It's not by accident that the king and queen haven't been to Cuba for 24 years and this visit will not go ahead by accident either,'' Aznar said.
Spanish officials have talked about scheduling the royal visit for sometime in the spring, but no date has been set.
The government has said the royals would have to be allowed to move freely and the visit would only go ahead if there was no ``atmosphere of repression.''
Spanish Foreign Minister Abel Matutes discussed the visit during a trip to Cuba last year that marked a normalisation of relations after a period of tensions between Aznar's centre-right government and communist leader Fidel Castro.
Copyright 1999 Reuters Limited