BOGOTA, Dec 16 (Reuters) - Colombia's central bank is expected to raise its benchmark interest rate on Friday, at its last meeting of the year, as persistent inflation pushes policy makers into postponing the close of the upward monetary cycle.

A Reuters poll earlier this week found that 13 out of 14 analysts expect the central bank to raise its benchmark interest rate by 100 basis points to 12% this month. Just one forecast a hike of 50 basis points to 11.5%.

"In our opinion, this decision would follow the fact that several arguments (for raising rates) presented by the board in past sessions are still valid and some of these have been accentuated," Bancolombia said in a statement to Reuters.

"The first and most important consideration is the increase in both observed inflation and the board's expectations," Bancolombia added.

Other reasons supporting the expected increase include a market consensus forecast that Latin America's fourth-largest economy will expand 7.8% this year, as well as the rhythm of rate changes in developed economies, Bancolombia said.

If the market expectation is met, the interest rate will hit its highest level since December 1999, and would be up 1,025 basis points since the bank began raising the rate in September last year.

Most analysts expect the decision will be split between the bank's seven board members.

The market majority now expects the bank to raise the rate again in January - previous expectations had forecast the upward cycle would end in December - after consumer price growth surprised upwards last month, pushing 12-month inflation to 12.53%, its highest level since March 1999.

According to the median of the survey results, the benchmark interest rate could finish 2023 at 9.75%, before falling to 6.25% at the end of 2024. (Reporting by Nelson Bocanegra Writing by Oliver Griffin Editing by Leslie Adler)