The blacklisted countries are accused of behaving like tax havens.
According to French Finance Minister Bruno Le Maire, the blacklisted countries could lose access to European Union funds.
British officials drew comfort from the exclusion of the Cayman Islands and Bermuda from the list; but their omission prompted an outcry from transparency activists, who dubbed the exercise a "whitewash". The EU said they could be included in an updated list.
The Paradise Papers leak, which made public some of the intricate ways corporations and individuals evade tax using offshore havens, has given new impetus to the bloc.
The EU says it updates the list at least annually.
South Korea slammed the European Union (EU)'s decision on Wednesday to put Asia's fourth-largest economy on a new EU blacklist of tax havens, saying that its inclusion is "not in accordance with worldwide standards" and poses the risk of "violating taxation sovereignty".
The EU's list is also questionable given the fact none of the 15 tax havens as mentioned in the 2016 Oxfam Releases List were not included in their list.
Though being hailed as a vital "first step", the failure of the member states to come to an agreement on any sanctions for those blacklisted provoked the European commissioner for economic and financial affairs, Pierre Moscovici, to openly admit it was as yet "an insufficient response".
Panama's president, Juan Carlos Varela, objected to his country being on the list, saying it is making progress against tax evasion.
Explaining the factors that led to the blacklisting of Namibia, Schlettwein said it was simply due to a deadline date miscommunication. Countries' inclusion is based on whether a state gives preferential treatment to companies enabling them to move profits to avoid charges. They also had to pledge to meet global transparency standards of the Organization for Economic Co-operation and Development, or OECD. Several other hurricane-impacted Caribbean islands have been put on probation and their cases will be addressed in February. Liberal Democrat leader Vince Cable accused Downing Street of helping the super-rich hide their cash.