 Vocal political dissidents opposed to Portuguese rule and claiming independence were typically forced into exile . From the mid @-@ 1920s a succession of authoritarian regimes in Portugal closed unions and left @-@ wing opposition , both within Portugal and within its colonies , notably in the <unk> Novo period ( 1933 @-@ 1974 ) . The Portuguese government forced black Mozambican farmers to grow rice or cotton for export , providing little return with which the farmers could support themselves . Many other workers — over 250 @,@ 000 by 1960 — were pressured to work on coal and gold mines , in neighbouring territories , mainly in South Africa , where they comprised over 30 % of black underground miners . By 1950 , only 4 @,@ 353 Mozambicans out of 5 @,@ 733 @,@ 000 had been granted the right to vote by the Portuguese colonial government . The rift between Portuguese settlers and Mozambican locals is illustrated in one way by the small number of people with mixed Portuguese and Mozambican heritage ( <unk> ) , numbering only 31 @,@ <unk> in a population of 8 – 10 million in 1960 according to that year 's census . 
