Nairobi —  Kenya will waive work and business permits for investors from its neighbour Tanzania, President Uhuru Kenyatta said on Wednesday, as his counterpart made similar overtures in a thawing of often frosty relations between the two countries.

Kenya, east Africa's biggest economy and one of its most liberal, and Tanzania, which still imposes fairly tight capital controls and is the region's second-largest economy, have long tussled for influence...