(Adds quotes, context)

BOGOTA, April 29 (Reuters) - Colombia’s central bank unexpectedly increased the benchmark interest rate by half a percentage point on Friday in an effort to stem rising inflation, and slightly lowered its 2016 growth forecast for the country’s oil-dependent economy.

A majority of the bank’s seven-member board voted to boost the lending rate to 7 percent, surprising most analysts in a Reuters survey, who had expected a quarter-point rise.

The bank expects economic growth to be between 1.5 percent and 3.2 percent this year, with 2.5 percent as the most probable outcome, said Jose Dario Uribe, a bank board director. That compares to a previous forecast of 2.7 percent growth.

The economy, fueled by consumer spending, will grow between 1.8 percent and 3.2 percent in the first quarter, with 2.5 percent as the most likely outcome, the central bank said in a statement.

Policymakers cited a sharp increase in food prices, a drought caused by the El Nino weather pattern, and the devaluation of the currency as reasons for the rate hike.

Colombia’s central bank embarked on a rate tightening cycle eight months ago in a bid to tame inflation, which is running at about double the upper end of the bank’s 2 percent to 4 percent target range.

“Despite being temporary shocks, the magnitude of the devaluation of the peso and the strength of El Nino have raised the risk of a slower convergence of inflation to the target,” the central bank said in its statement.

Although expressing continuing worries about stubbornly high inflation, it said Colombia’s fiscal risks had decreased due to unexpectedly higher oil prices and the recent appreciation of the peso against the dollar.

Economists estimate inflation will be as high as 8.12 percent in April.

“Inflation indicators won’t start to come down in April or May,” said Camilo Perez, chief economist at Banco de Bogota. “This won’t be the last of the rate increases.”

National income has been hit by the fall in prices for crude, Colombia’s most lucrative export and biggest source of foreign exchange. The country’s borrowing costs are the second highest in Latin America after Brazil.

Although the central bank’s board has been split in its recent rate decisions, many economists see the tightening cycle nearing an end, an opinion shared by board member Adolfo Meisel. He told Reuters last week that the pace of back-to-back, quarter-point increases in recent months is adequate, a possible indication of how he voted on Friday.

Fellow policymaker Carlos Gustavo Cano, however, has said Colombia requires additional, bigger rate increases to anchor inflation expectations.

The peso has gained recently against the dollar but is still down 19.4 percent over the past 12 months. That compares to a 31 percent depreciation for all of 2015.