The Salaries and Remuneration Commission has said MPs irregularly awarded themselves Sh250,000 monthly house allowances.
In a statement on Tuesday, SRC chairperson Lyn Mengich said SRC has the sole mandate of determining MPs' salaries and benefits.
It faulted the Parliamentary Service Commission for purporting to okay the allowances.
"The SRC has noted the media reports about the payment of house allowance Members of Parliament by the Parliamentary Service Commission. Article 260 of the Constitution categorises Members of Parliament as state officers and as such, payment of any remuneration and benefits, which have not been set or advised by the SRC is in violation of the Constitution," SRC said.
The SRC said the payment of allowances by PSC is a matter of "great public concern", adding it was reviewing the matter with a view of taking appropriate action.
The commission also raised concerns over the continued rise in the wage bill, hurting development plans.
MPs are hiding under the October 2018 judgment by justice Chacha Mwita who ruled that deputy governors just like other state officers are entitled to house allowance. They awarded themselves the backdated allowance in the April pay.
Each of the 416 MPs received Sh2.25 million over and above their monthly pay in April being the backdated amount for the contentious allowance.
For both the Senate and National Assembly, taxpayers will now be shouldering an extra burden of Sh 104 million every month to house the legislators who already have a subsidized mortgage scheme.
MPs are already entitled to Sh20 million mortgage charged at three per cent.
