* Opposition leader demands dialogue with government
* Government says Odinga creating crisis to stay relevant
* Politics in Kenya tends to follow ethnic loyalties
* Group of lawmakers also seek to end political stand-off
By Edmund Blair
NAIROBI, July 4 (Reuters) - Religious leaders in Kenya have urged calm ahead of an opposition rally next week that threatens to stoke tension in a nation scarred by political violence in the recent past.
Raila Odinga, the main rival Uhuru Kenyatta defeated in last year's presidential election, has set a deadline of Monday for the government to meet a demand for dialogue over militant attacks, corruption, a slow economy and other grievances.
Ministers have dismissed the call, saying the place for such debate is parliament. Kenyatta's aides accuse Odinga, a veteran former prime minister, of trying to engineer a crisis to claw his way back to power - a charge the opposition leader denies.
"As churches, we have all united in asking for peace and for calm in the country," Anglican Archbishop Eliud Wabukala told Reuters, speaking from his cathedral on the edge of the Nairobi park where Odinga will address the rally on Monday.
The 69-year-old former premier's complaints touch on public grumbles about insecurity after a spate of Islamist attacks and the rising cost of living. But many Kenyans, as well as foreign diplomats, also worry that Monday's rally could deepen rifts in a country where political loyalties tend to follow ethnic lines.
The nation is haunted by the 2007 presidential election, when 1,200 died in weeks of ethnic blood-letting - over which Kenyatta still faces trial at The Hague this year for crimes against humanity. However, last year's vote went off calmly.
The Roman Catholic Church called on both sides to "stop all political rallies", while Presbyterian moderator David Gathanju called on members not to attend Monday's rally. "We should not let the politicians make us ... quarrel or fight," he said.
The main churches claim about half of Kenya's 40 million people and could have a strong influence in a nation of regular churchgoers. The comments were also echoed by Muslim leaders.
"We have asked our members to stay at home or at work and avoid any such rallies for the sake of peace," said Khalifa Mohamed, secretary of the Council of Imams and Preachers of Kenya. About 15 percent of Kenyans are Muslim.
Kenyatta, an ethnic Kikuyu whose father was Kenya's first president after independence from Britain, added to the mounting tensions when he accused local politicians of being behind attacks last month on Mpeketoni coastal area that left 65 dead. Opponents saw it as a reference to Odinga, a Luo.
"The politicians with their pronouncements are lighting the tinderbox if they are not very, very careful," said one Western diplomat, echoing comments by other envoys.
The 52-year-old president dismissed claims by Somalia's al Shabaab Islamists that they were responsible for Mpeketoni, although the group has been blamed for other attacks in Kenya.
Odinga has called for a rally and holiday on "saba saba", the Swahili term for 7/7 or July 7, a date full of symbolism as it recalls the day in 1990 when opponents - including Odinga - of then autocrat Daniel Arap Moi demanded politics be opened up.
Odinga has not said what will happen if his deadline passes without government action. But he has promised more rallies.
The Federation of Public Service Trade Unions issued a statement telling state workers Monday was not a public holiday. The head of Kenya Private Sector Alliance said rallies could get out of hand if not managed well, newspapers reported.
Police promised to secure rallies and prevent any clashes.
A group of about 15 lawmakers, most from Kenyatta's Jubilee and some from the opposition CORD coalition, met Odinga on Thursday to try and stop the rally, offering a debate in parliament. Odinga, who has held several smaller, peaceful gatherings lately, called parliament "part of the problem".
However, having challenged the outcome of last year's election, which marked his third failed bid for the presidency, he has since accepted a court ruling upholding the result. (Additional reporting by Joseph Akwiri in Mombasa and Duncan Miriri in Nairobi; Editing by Alastair Macdonald)