BOGOTA, May 30 (Reuters) - Colombia's central bank board is expected to raise interest rates by a quarter percentage point on Friday on top of the same increase last month, as growth gathers momentum and policymakers seek to head off a moderate rise in inflation early on.
Thirty of 36 analysts surveyed in a Reuters poll on Monday expected a 25 basis point rise for the second straight month, which would take borrowing costs to their highest since January 2013.
"Inflation is not easing and neither is the economy weakening. ... Based on this it's advisable to raise the rate to avoid a heating-up in the future and financial disorder," said Miguel Medellin, head of research at the Asobancaria banking industry association.
The other six analysts expected the bank to raise rates but slower, while they observe the direction of economic indicators. April 12-month inflation at 2.72 percent, was the highest since October 2012. It had dipped to its lowest since 1955 last year.
"After April's 25 bp increase, we expect the next hike in June and the rate to rise to 4.5 percent by December 2014," Merrill Lynch said in a bulletin.
A majority of analysts surveyed said the benchmark rate will rise to 4.25 percent to 4.5 percent by the end of this year, and between 5 percent and 5.25 percent by the close of 2015.
Colombia is in the middle of presidential elections but the outcome of a second round vote on June 15 is seen as innocuous for the economy. Both finalists, incumbent President Juan Manuel Santos and right-wing Oscar Ivan Zuluaga are former finance ministers with a reputation for pro-business policies.
Policymakers are not expected to adopt any additional policy measures, most analysts said. The Andean nation's existing dollar buying program to build reserves and weaken the peso, runs until the end of June.
Colombia's economy has grown at 4 percent or more since 2010 with expansion forecast for this year. A negative output gap, or spare productive capacity, has kept inflation low.
"Recent surprising increases in terms of inflation have given the bank room for more aggressive normalization of monetary policy," said Sergio Zafra, analyst at the Asesorias e Inversiones brokerage.
"As well as that, the rise in indicators like industrial output and trade provide evidence that the economy will reach its potential growth this year," Zafra said.
Commodities account for a large share of output, with rising oil output now around 1 million barrels per day, large coal exports and the world's biggest harvests of mild arabica coffee.
Central bank chief Jose Dario Uribe said this month that the economy probably grew 4.8 percent in the first quarter and that inflation looked set to hit around 3 percent this year, the center of the bank's target 2-4 percent range.
The statistics agency will publish the first quarter growth figure on June 19. (Editing by Andrew Hay and Richard Chang)