Classes were cancelled all across Niger on Wednesday and health centres were functioning at a minimum after unions called for workers to go on strike for 72 hours to demand higher salaries.

"Living conditions must improve now,” said Chamsou Issaka, a spokesman for one of the teachers’ unions, speaking on a local radio station on Wednesday.

The unions are seeking to improve salaries and benefits for 24,000 teachers who work on contracts rather than as permanent civil servants as do 4,000 others.

Contract teachers, students and health workers frequently go on strike in Niger, a vast, arid country with few resources.

Hassoumi Djibo, a leader for the health workers’ union, threatened to take the current 72-hour strike to a “higher level” if the government does not agree to improve salaries and conditions for the 6,000 nurses, mid-wives and laboratory assistants represented in the union.

Government spokesman Mohamed Ben Omar said on national television on Tuesday that the unions broke off negotiations just when the government had agreed to increase salaries. He said salaries “must be compatible with the capacities of the state”.

Currently the salary of a high school teacher is around 60,000 CFA (US$121) a month, while a primary school teacher earns about 40,000 CFA ($80) per month.

Before the strike began the government threatened not to pay workers for the period they went on strike. "When civil servants are absent, whether observing a strike or not, they are held responsible and their pay and benefits will be cut [for the days they missed],” Ben Omar said on Tuesday.

However, many teachers appeared to have ignored the warning.

The literacy rate in Niger is amongst the lowest on the world, according to the United Nations Human Development Index, with almost eight adults in 10 unable to read or write.