Nigeria's police chief came under increasing fire on Thursday over the escape from custody of the alleged mastermind of a Christmas Day church attack that killed at least 44 people.

Police Minister Caleb Olubolade on Wednesday gave police inspector general Hafiz Ringim 24 hours to produce a report explaining circumstances leading to the escape of Kabiru Sokoto, accused of belonging to Islamist group Boko Haram.

Police could not confirm whether the report had been filed, but said a 50 million naira ($310,000/240,000 euros) reward had been offered for information leading to the suspect's arrest.

Sokoto is believed to be behind the December 25 bombing of a church in Madalla near the capital Abuja that claimed the lives of at least 44 worshippers. Another five people were killed in other attacks the same day in the troubled north of the country.

His disappearance is an embarrassing blow to President Goodluck Jonathan, who has deployed hundreds of troops and imposed emergency rule in parts of four states in a bid to curb intensifying attacks blamed on Boko Haram.

Suspicions have been raised over the suspect's escape, amid long-standing allegations of links between Boko Haram members and politicians. Nigeria's police force is also riddled with corruption.

Ayo Oritsejafor, the head of Nigeria's main Christian organisation CAN, said it was "clear that the man was definitely helped to escape".

"It was an arranged escape, so they should hold responsible all those involved and they should produce the man," he said, describing it as a "huge national embarrassment".

But even the circumstances of the suspect's arrest were shadowy.

Sokoto was arrested at a lodge in Abuja belonging to the governor of the northeastern Borno state, which is regarded as the base of Boko Haram.

Inwa Bwala, the state information commissioner, suggested the man was smuggled into the lodge by a Borno native who was spending Saturday there awaiting a flight to Britain.

"As a government, we feel embarrassed that the incident happened at our lodge, but we have our suspicions," Bwala said.

"We actually suspect that some people are trying to create the impression that the Borno state government has some form of romance with Boko Haram, just to give us a bad image," he told AFP.