South African maize farmers are expected to plant 18% less of the staple crop this season due to dry and hot weather along the western part of the maize belt, a Reuters poll showed on Friday.

South Africa's Crop Estimates Committee (CEC) is expected to forecast the planted area at 2.159-million hectares, down from 2.629-million hectares planted last season when favourable weather conditions boosted yields, according to an average estimate of seven traders and analysts polled by Reuters.

The range of total maize estimates was 1.910-million to 2.430-million hectares.

"The western regions of the country, which largely produce white maize, were unable to meet their planting intentions due to persistent dry and warm weather conditions," said Wandile Sihlobo, an economist at the agricultural business chamber.

The average estimated from the poll pegs the crop at 1.148-million hectares of white maize, used for human consumption, and 1.012-million hectares of yellow maize used mainly in animal feed.

Yields in the North West and Free State provinces could also be impacted by hot and dry weather, analysts said.

"The intense heat wave will definitely impact negatively on yields if it does not rain more in the next few weeks as the crops head into a critical stage of development," said Paul Makube, senior agricultural economist at FNB bank.

Concerns over plantings and yields for the 2017/18 season saw maize prices hit 11-month highs of R2 123.80/t last week. The contract for delivery in May has since given up some of its gains and was around R1 933/t on Friday.

Industry group Grain SA said farmers in the western part of the maize belt have only planted 70% to 75% of the area they had intended because of drought during the best planting period.

The CEC will issue its preliminary forecast for the area planted for the 2017/18 maize growing season on Tuesday.