The bullet-riddled bodies of five aid workers have been found, weeks after they were abducted by armed gunmen in the volatile south of Afghanistan.

The group of Afghan workers for Save the Children was snatched by armed gunmen in Trinkot, capital of the strife-torn Oruzgan province, on March 3.

A spokesman for the provincial governor has blamed the Taliban for their deaths after their bodies were found on Friday, saying the militant group had demanded a prisoner exchange.

"The Taliban had kidnapped the aid workers and were demanding the release of some of their colleagues in government custody," Dost Mohammad Nayab said on Saturday.

"After their demand was rejected, they shot and killed the aid workers. We found their bodies in Chanarto district yesterday."