UPDATE 4-Kenya's Ruto says no time to waste after election as rival prepares court challenge

* Ruto declared president-elect on Monday

* Opposition leader Odinga to contest the decision in court

* Kenya faces mounting economic, unemployment, debt crises (Adds statement by election commission chair)

By George Obulutsa

NAIROBI, Aug 17 (Reuters) - Kenya's president-elect William Ruto said on Wednesday there was no time to waste in tackling an economic crisis, as defeated rival Raila Odinga prepared a legal challenge to overturn his loss in Aug. 9's election.

Ruto was declared president-elect on Monday by Kenya's election commission chairman after a closely fought race to lead East Africa's richest country, but four of the seven election commissioners have challenged the results.

Odinga has said he will contest the decision in court, calling it a "travesty".

Ruto nevertheless said he was forging ahead with creating an administration, promising that no Kenyan would be excluded, whatever their political or ethnic affiliation.

"I really want us to know that the expectations of the people of Kenya are huge. We don't have the luxury of wasting time," Ruto, currently deputy president, said after meeting elected officials from his alliance at his official residence.

The 55-year-old did not directly address Odinga's plan to challenge his victory, but said: "If there will be court processes, we will engage because we adhere to the rule of law."

The election was seen as a test of stability for a close Western ally that hosts regional headquarters of multinational firms such as Alphabet Inc. The United Nations Environment Programme is headquartered in Nairobi.

At a separate meeting in the capital, elected officials from Odinga's alliance met to chart their next steps in what could be a bruising legal battle.

Odinga did not speak at the event but his running mate, Martha Karua, a former justice minister, said: "Ours is victory deferred."

Odinga later tweeted: "We are confident that we shall overcome the chicanery and reclaim our victory in due course."

Odinga, 77, a former prime minister who was making his fifth run for the presidency, has until Monday to file a petition at the Supreme Court.

Election commission chairman Wafula Chebukati rejected claims by the four dissenting commissioners that the tallying process was opaque.

In a statement, he accused them of demanding prior to the official declaration that he "moderates the results for purpose of forcing an election re-run".

"This is tantamount to subverting the constitution and the sovereign will of the people of Kenya," Chebukati said.

Contacted by Reuters, commission vice-chairwoman Juliana Cherera, who has been the dissenters' main spokesperson, declined to respond.

The Supreme Court said on Wednesday it was ready to handle any petition and was making preparations just in case.

'NO MONEY'

President Uhuru Kenyatta's successor will have to tackle a surge in food and fuel prices triggered by the war in Ukraine, rising unemployment, and a mountain of debt used to finance development through Kenyatta's 10 years in office.

Kenyatta, who backed Odinga and criticised his deputy as unreliable, has said borrowing built infrastructure and spurred growth. The economy has doubled in size over the past decade.

Critics say the government left many vulnerable people behind while it focused on roads and railways.

Ruto's campaign to become Kenya's fifth president focused on uplifting low-income "hustlers" but policy analysts see little fiscal room for him to deliver quick relief.

"There isn't the money," Robert Shaw, an independent economic policy analyst, said. "The government already has huge domestic debt, has hardly enough revenue to pay wages."

With high debt limiting scope for any subsidies, Aly-Khan Satchu, the CEO of investment adviser Rich Management, advocated giving priority to food staples.

"If it was the devil's choice, I would maintain the unga (flour) subsidy over everything else."

($1 = 119.4000 Kenyan shillings)

(Reporting by George Obulutsa; Additional reporting by Ayenat Mersie; Writing by James Macharia Chege and Aaron Ross; Editing by Catherine Evans and Tomasz Janowski)