In a public statement on Saturday, the government said that treason charges against former attorney-general Muhammad Munawwar and former tourism minister Ibrahim Zaki had been dropped.
Charges against special constitutional assembly member Ibrahim Ismail and Qasim Ibrahim, one of the country's wealthiest businessmen, have also been abandoned.
The four were among about 200 people detained following an unprecedented pro-democracy rally in August.
They were later freed pending trial for the treason charges, which carry a maximum penalty of 25 years in prison.
Government spokesman Ahmad Shahid added that the country needed to focus on reconstruction after last weekend's devastating tsunami.
Public disorder charges against 20 people were also dropped on Friday, and the government said it would no longer pursue investigations into the political activities of a number of others.
Shahid added that authorities might accelerate moves toward democratic reform in the tiny island nation. "This is a defining moment in our political evolution."
The announcement followed the worst natural disaster in the Maldives' history.
The death toll from the tsunami stands at 73 with 31 people still missing, and officials estimate the cost of the damage may exceed the country's annual gross domestic product.
Political prisoner releases
Abd al-Qayum, who has ruled the Maldives with an iron fist for 26 years, has faced growing calls for political reform.
In June 2004, al-Qayum announced he would move toward political reforms including establishing multi-party democracy, separating the executive, legislative and judicial branches of government, and decentralising the administration.
The opposition has accused him of lacking sincerity.
Parliamentary elections scheduled for 31 December have been postponed until 22 January due to damage caused by the tsunami.