The East African nation born of the merger of Tanganyika and Zanzibar holds a referendum on a constitution that will affect the general elections expected in Oct 2015.
Opposition lawmakers are reported to be angry because the proposed constitution rejected their calls for strengthening the federal system and limiting the powers of the president.
One-party rule ended in 1995 with the first democratic elections held in the country since the 1970s.
The ruling Chama Cha Mapinduzi (CCM) party drafted the new constitution in the absence of opposition lawmakers, who boycotted the drafting process and reject the draft charter. The CCM has been in power since independence.
The proposed constitution allows for an independent electoral body, one of the demands of the opposition. It sets limits on how many cabinet ministers the president can appoint and introduces equal representation of men and women in parliament. It also grants women equal land ownership rights.
Date written/update: 2015-02-25