Two Nigerian election officials were sentenced to seven years in prison on Friday after accepting bribes from the country's former oil minister to rig the 2015 election.

Christian Nwosu and Tijani Bashir were found guilty at a court in Lagos on Thursday of receiving 264.8 million naira ($730 500) from Diezani Alison-Madueke.

Alison-Madueke, a former head of OPEC, served as minister of petroleum resources under president Goodluck Jonathan until his defeat to Muhammadu Buhari at elections four years ago.

She has since been linked to a string of money laundering, bribery cases and investigations in Nigeria and abroad.

Sentencing the pair, who worked for the Independent National Electoral Commission, Judge Mohammed Idris said they acted "in breach of their duty" and brought the body into disrepute.

"The INEC officials must know that their conduct must meet the required standard and must be responsible and accountable," he added.

"This country must not be allowed to degenerate to anarchy... The message should be sent to INEC that anyone found guilty will be dealt with according to the provisions of the law."

Presidential and parliamentary elections are scheduled for February 16, with governorship and state assembly polls two weeks later.

Nwosu was ordered to forfeit to the government land and property in the southern state of Delta worth 25 million naira and cash totalling five million naira.

Bashir was told to hand over a 27-million-naira property in the capital, Abuja.

A third INEC staff member, Yisa Olanrewaju Adedoyin, pleaded guilty to receiving 70 million of the 264.8 million naira at a hearing in May 2017.

He was fined 10 million naira and forfeited land as part of a plea bargain, the country's Economic and Financial Crimes Commission (EFCC) said.

The anti-corruption body said the election officials "reasonably ought to have known" that the money they received formed "part of the proceeds of an unlawful act".

The EFCC alleges that Alison-Madueke distributed a total of 23 billion naira ($63.4 million, 55.7 million euros) around the country to try to influence the result.

The former minister has been on bail since being arrested in London in October 2015 in connection with an international corruption probe.

EFCC chairperson Ibrahim Magu wants her to be extradited to face trial in Nigeria, arguing that the criminal investigation in Britain is taking too long.