The announced release would be the largest since 1998, when 101 political prisoners were among about 300 prisoners freed following a visit by Pope John Paul II.
It follows recent dialogue between Raul Castro, the country's president, and Cardinal Jaime Ortega, the Cuban Catholic leader, and comes after Miguel Angel Moratinos, the Spanish foreign minister, met Cuban officials in Havana on Tuesday.
Juan Jacomino, a journalist in Havana, said there has been no official communique from the government about the imminent release of the prisoners.
"Public opinion in Cuba is still not too well informed about this. The Cuban government usually takes time before it spreads out things like this," he told Al Jazeera.
"There are certainly going to be greater national repercussions ... because while the Cuban public opinion is more concerned about the hardships of daily life, this is certainly a major development ...
"Some people I have spoken with have said that this might be the tip of the iceberg in the sense of an announcement of larger reforms, economic and social reforms that are badly needed in Cuba ... "
Cuba came under heavy international criticism after the February 23 death of hunger striking dissident Orlando Zapata Tamayo.
It has since begun to relax its policy toward dissidents, who it consider mercenaries working for the United States.
Another dissident, Guillermo Farinas, has been on a hunger strike for 134 days, seeking the freedom of 25 ailing political prisoners, who are believed included in the group to be released.
The dissidents were among 75 people arrested in 2003, many of whom now are in ill health.