Diplomats from the US, British and German embassies looked on as Niyazova made a 10-minute statement from a cage inside the courtroom.
The statement was critical of Human Rights Watch. The group's researcher in Uzbekistan, Andrea Berg, was accused of bias and harming the country.
|Hundreds were killed during protests in|
Andizhan in 2005 [EPA]
Human Rights Watch said it welcomed Niyazova's release, but it did not comment on the criticisms of its work.
In the statement, Niyazova also criticised "colour revolutions" - a term applied to popular uprisings in three former Soviet states; in two of them, Georgia and Ukraine, the uprisings brought Western-oriented governments to power.
"I would not want a colour revolution to take place in Uzbekistan like it happened in Georgia, Ukraine and Kyrgyzstan," she said.
After a two-day trial last week, Niyazova, who also wrote news stories critical of the Uzbek government, was sentenced to seven years in jail.
She was found guilty of smuggling subversive literature, illegally crossing the border, and illegally financing local rights groups with funds from unnamed foreign embassies.
Uzbek authorities found articles and information in her laptop computer about the killing of protesters in the Uzbek town of Andizhan in May 2005.
The EU and US had criticised Uzbekistan over the case.