Inflation is usually posted by the Central Statistics Agency (CSA) in the first week of the subsequent month, but in an unusual delay December data was still not up by Thursday.

"I have been reporting about inflation for the past six consecutive years and I have never seen such a delay," said one Ethiopian business journalist based in Addis Ababa, who asked not to be identified for fear of reprisals.

The statistic agency's director Biratu Yigezu and spokesman Safi Gemedi did not respond to questions.

In November, inflation (ETCPIY=ECI) was 33% year-on-year, down from 34.2% in October and 34.8% in September, which World Bank data showed to be the highest since 2008.

A more than year-long war in Ethiopia's northern Tigray region, inter-communal violence and drought have damaged the economy and pressured food costs.

Last month, Ethiopia proposed a 122 billion birr ($2.5 billion) supplementary budget to finance and rebuild areas destroyed by war and provide humanitarian assistance.

Reporting by Dawit Endeshaw, Editing by Ayenat Mersie and Andrew Cawthorne