Zimbabwe has bought 100,000 tonnes of maize from Tanzania amid a huge shortage of the food staple caused by the country's worst drought in 40 years, reports Bloomberg news site.

The drought and flooding that followed Cyclone Idai, which swept through the region earlier this year, has cut the maize harvest in Zimbabwe, once a regional bread basket, by half, it adds.

At the beginning of August, the UN's food agency warned that 2.3 million rural Zimbabweans were on the cusp of starvation.

"Widespread poverty, HIV/Aids, limited employment opportunities, liquidity challenges, recurrent climate-induced shocks and economic instability all contribute to limiting adequate access to food," the World Food Programme (WFP) says about Zimbabwe.

The maize will be transported from Tanzania by rail, Bloomberg says.