"Collusion, wanton bribe-taking and general corruption continue to pervade operations of KRA (Kenya Revenue Authority)," President Ruto told KRA's management and board members at an event beamed live on his social media pages.
The government's efforts to boost tax collection were being hampered by unscrupulous staff at KRA, he said, who spent their time helping corrupt taxpayers to evade paying.
Ruto also accused KRA staff of resisting and sabotaging attempts to digitize revenue collection in the past, to prevent the government from sealing loopholes.
"I have to be candid because I have a job to do," the president said.
In terms of tax collected as a proportion of annual economic output, Kenya has been underperforming other nations like South Africa, Ruto said.
KRA declined to comment.
Kenyan authorities have been fighting corruption and the tax collection agency has come under scrutiny. In May 2019, 75 KRA staff were arrested on suspicion of abetting tax evasion and bribery.
KRA has not issued its latest tax collection figures but local media outlets said it collected 1.57 trillion shillings ($11.50 billion) in the 10 months to the end of April, meaning it has just two months to meet the government's target of 2.1 trillion by the end of June.
Ruto, who was elected last August on a platform of helping the poor, has had a rough ride in the first months of his term due to growing government debt repayments, revenue collection shortfalls and persistently high prices of basic commodities.
To shore up revenue, his administration has proposed a raft of tax increases in spending proposals that will be presented to parliament next month, angering citizens and the opposition.
"The (finance) bill prepared by the Kenya Kwanza regime is a punishment that Kenyans cannot and should not entertain," the opposition Azimio coalition said this month, referring to Ruto's Kenya Kwanza political coalition.
Forum