Amara Konneh's efforts to rebuild the economy of war-torn Liberia won him the award two years ago from the influential Banker magazine, which is published by the Financial Times.
On Tuesday, however, the Liberian Senate ordered his arrest after he refused to apologise for sending them a letter telling them to cut their personal allowances.
The country, which had its economy ravaged by 2014's Ebola outbreak, needs to shave nearly $70m from its annual government budget. News of his arrest has outraged colleagues, who say that Mr Konneh is being punished for simply doing his job.
"The senate is angry about Mr Konneh's proposal to cut their budget," said James Kollie, his deputy. "They will have to cut their budget by about $1.2m, which will mean they will lose out on things like vehicle allowances, home allowances, and other things. This is all about their personal perks. It is an abuse of power, and a means to try to intimidate him so that they cannot be cut."
Mr Konneh said that shortly after his arrest was ordered, the threat was temporarily lifted after a member of the Senate filed a motion for reconsideration of the order. But his imprisonment will go ahead unless the motion wins a majority in the senate during a vote in coming days, which seems an unlikely prospect.
Liberia, which was ravaged by a brutal civil war in the 1990s, is one of the poorest countries in the world, and was brought to the brink of collapse by the Ebola outbreak, which killed nearly 5,000 people.
It also devastated the economy as businesses folded or and foreign investors pulled out.
Mr Konneh is one of a new generation of African economists who have won global plaudits for their efforts to end the public corruption and wastefulness of the past.
The Banker magazine, which is one of the best-read financial publications in the world, presented him with an award for African Minister of the Year in a ceremony in London in 2014.
He was praised for helping the government rebuild its security services and attract outside investment. Culled from The Telegraph.
By Colin Freeman, Chief foreign correspondent