A decision by Kenya's parliament to exempt Japanese companies, consultants and employees from income tax has sparked an uproar.

The vote passed on Wednesday targets those involved in projects financed by the government of Japan.

The government said the benefits of the deal were greater than the forgone taxes.

But Kenyan civil societies have vowed to go to court to challenge the exemption, arguing that it is prone to abuse as it lacks clarity.

"It is not very clear what you define as a Japanese business. What would stop an Indian business from going to Japan, registering as a Japanese business and then come in to take advantage of similar exemptions," Alvin Mosioma of Tax Justice Network Africa told local Citizen TV.