Equatorial Guinea's main opposition party Citizens for Innovation (CI) has been banned, the party confirmed.
DW Radio Monday quoted CI leader Nsé Obiang Obono confirming the ban imposed by a court.
"It is President Teodoro Obiang Nguema who opted to outlaw the party," Mr Obono was quoted saying.
A court last year ordered CI's dissolution and sentenced 30 of its members to jail.
According to the court, the CI members were found guilty of engaging in immorality and each sentenced to 41 years in jail.
CI was also accused of attempting a coup d'état against President Nguema.
The Equatorial Guinea government said in January that it had thwarted a coup d'état in late December, mounted by mercenaries.
In a statement read on national radio, Security minister Nicolas Obama Nchama said: "Mercenaries... were recruited by Equatorial Guinean militants from certain radical opposition parties with the support of certain powers."
President Nguema is Africa's longest-serving leader, who has ruled the former Spanish colony for 38 years. He has been repeatedly accused of human rights abuses.
Equatorial Guinea, though Spanish-speaking, applied to join the Portuguese-speaking lusophone bloc in 2006 and was admitted.
The country on the west coast of Africa, has a population of 740,000 people occupying a mainland territory called Rio Muni and five small islands, including Bioko, where the capital Malabo is located.
In 2015, before the country formalised joining the Portuguese-speaking bloc, Amnesty International said its authorities had killed nine opposition members.
In 2016, the Malabo government said it had abolished the death penalty.
In January, Equatorial Guinea authorities denied human rights violations and having political prisoners as suggested by the Portuguese parliament.
The ruling Equatorial Guinea Democratic Party (PDGE) dominates the legislative and municipal assemblies.
PDGE has been in power for 40 years and rules with its allies.