Kenyan Prime Minister Raila Odinga on Saturday declared the appointment of top judicial figures by the country's president null and void because he had not been consulted.
President Mwai Kibaki named a new Chief Justice, Attorney General and Director of Public Prosecutions late on Friday while Odinga was in Ethiopia at an African Union summit.
The appointments are part of reforms to improve public confidence in the judiciary and are also designed to cement the east African country's case to hold any trials of post-election violence suspects in Kenya, rather than The Hague.
Kibaki nominated Justice Alnasir Visram, a justice of the Kenya Court of Appeal as the next Chief Justice. He also named lawyers Githu Muigai for the post of Attorney General and Kioko Kilukumi as Director of Public Prosecutions.
However, Odinga said he should have been consulted, in line with the constitution, and that Kibaki's move was a major setback to reforms agreed after the 2008 violence that killed some 1,300 people and uprooted more than 300,000.
Without a doubt this decision has thrown the country into a major constitutional crisis and may be the beginning of the end in respect of the implementation of the reform agenda if not corrected and reversed, Odinga said in a statement.
The row is a further sign of a deepening rift in the cabinet, which emerged after Odinga criticised Kenya's move to seek African Union backing in delaying trials of post-election violence suspects at The Hague.
Odinga said the legal appointments were designed to protect certain members of Kenya's ruling class and would perpetuate the culture of impunity that has dogged the country for decades.
The appointments have been made to serve the interests of a few people, including elements within upper echelons of government who have serious credibility and integrity issues and constitute the networks of impunity, Odinga said.
Muigai is a renowned lawyer from Kibaki's ethnic group and is also accredited to the International Criminal Court. Odinga had been pushing to have one of his allies appointed.
The new Director of Public Prosecutions, Kikoko Kilukumi, is is another respected lawyer, who is also defending suspended cabinet minister William Ruto in a $1.2 million graft case.
Ruto is one of six people named by International Criminal Court prosecutor Luis Moreno-Ocampo as the main suspects behind the deadly post-election violence that followed a disputed presidential election.
With the new officials in place, Kenya's government is hoping to convince the ICC that its discredited judiciary, which surveys show few citizens have little faith in, has been sufficiently reformed to prosecute the suspects.
ICC pre-trial judges are due to rule in March on whether the six suspects named by the prosecutor have a case to answer.
The row between Kibaki and Odinga also sets the stage for a parliamentary showdown as the appointments must be now ratified by the national assembly.