INTERVIEW-Somalia faces worst drought in five years - UN

* Agencies unable to reach most malnourished children * Food prices up 75 pct in 6 months, worsened by hoarding

* Rebels refuse food aid, say it encourages dependency

By Katy Migiro

NAIROBI, Jan 28 (Reuters) - Somalia is entering its worst drought in five years and aid agencies are unable to feed the majority of people in need, a senior United Nations humanitarian official said on Friday.

Al Shabaab rebels, who profess loyalty to al Qaeda, have refused to allow food aid to be distributed in southern and central Somalia, which they control.

"It looks as if we are now going into something that last happened five years ago, which is an acute drought cycle," Mark Bowden, the U.N. Humanitarian Coordinator for Somalia, said in an interview with Reuters.

"Clearly the issue of food distribution is going to become more and more pressing."

The number of Somalis in need of aid has increased by 20 percent in the last six months to 2.4 million, 32 percent of the population of 7.5 million, according to the Food and Agriculture Organisation's (FAO) unit report on Somalia.

Bowden said half the population might require aid as the drought intensifies. He said the rebels were unwilling to negotiate with the U.N. because they did not believe food aid was necessary.