Zimbabwe's justice ministry says the head of the nation's election commission has resigned for health reasons weeks away from a referendum on a new constitution followed by elections later in the year.

The ministry said Wednesday that Judge Simpson Mutambanengwe will leave his post on Feb. 20. It says a successor will be appointed from nominees listed by an all-party panel of lawmakers.

The elderly jurist, who began his legal career in Britain in 1963, became head of the Zimbabwe Electoral Commission in 2010 after it was reformed to include members not chosen solely by President Robert Mugabe's former ruling party. In the past year, the independent Mutambanengwe had largely withdrawn from the daily running of the commission through poor health.