The director of the Tanzania Media Women's Association (Tamwa), Ananilea Nkya, was arrested early today in Dar es Salaam.
She was detained along with several activists and journalists during a public demonstration calling for the government to resolve an ongoing doctors' strike.
Several hospitals have been closed during the strike by junior doctors and medical interns, which began on 30 January. They are protesting about pay and working conditions.
Some specialists have also joined the strike, and the Tanzanian government has come under mounting pressure to resolve the dispute.
The reason for Nkya's arrest remains obscure. She did make a statement yesterday about the need "to make the public disabuse themselves of the commonly held belief that prominent people care little about what is going on because they can access medical attention outside Tanzania."
But concerned supporters do not believe that to have been the reason for her detention.
Sources: Daraja/AllAfrica.com/IPPmedia/The Citizen