Civil society groups on Sunday threatened to move to court this week to block the Sh2 billion send off perks for MPs.
The groups' president Morris Odhiambo says the move was unconstitutional and they want the court to declare it illegal.
"I know we have gone to court several times on questions to do with Members of Parliament. For example our case on their taxation issue, is still pending in court, but we shall still pursue this matter through the courts because of the unconstitutionality of the decision they made," Odhiambo said.
Speaking to Capital News, Odhiambo appealed to President Mwai Kibaki and Prime Minister Raila Odinga to intervene and block the payments by not signing the amendment in the Finance Bill.
The Civil society groups have also indicated that they will hold a demonstration against the MPs starting Monday.
"If we let any decision that is illegal to pass then we shall be even setting the wrong precedent for this country and we might find ourselves in a situation where we are abusing the law, right left and centre which seems to be what these leaders prefer," added Odhiambo.
"How come our teachers had to strike for three weeks to get a salary hike, yet within a single sitting the MPs could easily increase their remuneration. So where is the Sh2 billion going to come from?" he asked.
Meanwhile Deputy Prime Minister Musalia Mudavadi has called on the two principals not sign the amendment into law.
"In view of the existence of the Salaries Review and Remuneration Commission (SRRC) and agitation by the public, Parliament may have sent a negative signal with this award. I ask the President to hold his assent to allow the agency do its work," said Mudavadi.
MPs on Thursday sneaked in an amendment that would see each of the 222 members get close to Sh10 million as a send off package, at the end of their current terms.
This comes at a time when Finance Minister Njeru Githae has proposed to increase taxes to raise over Sh40 billion required to meet public servants' recent wage demands.