* March 4 vote first since bloody 2007 polls
* Claims of plans to rig election raising tensions
* Police to probe threats to judiciary
By James Macharia
NAIROBI, Feb 21 (Reuters) - Kenyan Prime Minister Raila Odinga on Thursday accused the head of the civil service of recruiting officials to back his main rival's presidential campaign as part of a wider plan to rig the election next month.
Analysts warned the infighting in top government ranks may raise tensions ahead of the closely-watched March 4 vote, the first since a disputed presidential contest unleashed violence that took the country to the brink of civil war five years ago.
Odinga, who narrowly leads Uhuru Kenyatta in opinion polls ahead of the presidential vote, said the plot centred around Francis Kimemia, cabinet secretary and chief civil servant, and included plans to intimidate courts and coerce village administrative officials to back his rival.
"We see a pattern emerging which is very akin to what we saw in 2007, civil servants being involved in the campaigns," said Odinga, who has written to the electoral commission to complain.
Kimemia denied involvement in any rigging plot and ordered a probe into the allegations by police and intelligence services.
On Wednesday, Kenya's chief justice said he and other judges had been threatened by criminals who told them not to try to stop Kenyatta running for the presidency.
Kenyatta, a deputy prime minister, former finance minister and the son of the country's founding president, is one of four Kenyans accused at the International Criminal Court of orchestrating post-electoral violence in 2007.
Odinga said the threats reported by the chief justice were part of a vote-rigging plot.
After the last presidential vote in 2007, protests by supporters of then opposition leader Odinga erupted into widespread bloodletting after he disputed the result, which declared incumbent President Mwai Kibaki the victor.
More than 1,200 people were slaughtered, many butchered by machete, burnt alive or shot with bows and arrows, as the country's biggest tribes turned on one another.
Kenyatta's spokesman said Kimemia was in no way helping the deputy prime minister's campaign for presidency.
"Mr Odinga should lay off the civil servants and let them do their work," spokesman Munyori Buku said in a statement.
Ethnic rivalries fed 2007's fighting, which damaged the image of the East Africa's most powerful economy and a key ally in the U.S.-led war against militant Islam in the region.
"The claims by the prime minister are raising concern. It could be a way of preparing to reject the election results once they are announced," said Macharia Munene, a lecturer on international relations at the United States International University in Nairobi.
Adams Oloo, a professor of political science at the University of Nairobi said: "There's a question mark over the upper echelons of the civil service, is there some meddling going on? These questions are raising temperatures." (Reporting by James Macharia; Editing by Jason Webb)