Nigeria has removed more than 20,000 non-existent workers from the government payroll following an audit, leading to savings of 2.29bn naira (£8.3m) from its monthly wage bill, the finance ministry has said.

Corruption and mismanagement have long stunted development in Africa’s biggest economy and top oil producer, and are now exacerbating the impact of a sharp fall in global crude prices.

The audit used biometric data and a bank verification number (BVN) to identify holders of bank accounts into which salaries were being paid.

This showed the names of some civil servants receiving a salary did not correspond to the names linked to the bank accounts. In some cases individuals were also receiving salaries from multiple sources.

“The federal government has removed 23,846 non-existent workers from its payroll,” said Festus Akanbi, special adviser to finance minister Kemi Adeosun who took office in November and soon after set up an efficiency unit to cut waste.

“Consequently the salary bill for February 2016 has reduced by 2.293bn naira when compared to December 2015 when the BVN audit process commenced,” said Akanbi, adding that those removed had been paid by ministries, departments and agencies.

The ministry said it would now undertake “periodic checks and utilise computer-assisted audit techniques” and also introduce tougher monitoring of new entrants to the civil service to avert further abuse of the system.

The administration of President Muhammadu Buhari, who took office last year vowing a crackdown on graft, said it wanted to cut the costs of running the government rather than slash jobs to help tackle Nigeria’s worst economic crisis in years.

“The ongoing exercise, which is part of the cost-saving and anti-corruption agenda of President Muhammadu Buhari’s administration, is key to funding the deficit in the 2016 budget,” said Akanbi.

The ministry, which said personnel costs represent more than 40% of total government expenditure, said it had so far checked the details of about 312,000 civil servants.

Akanbi said the ministry was working with the financial crimes agency and the National Pension Commission to identify irregularities and recover salaries and pension contributions related to the deleted workers.