Chinyere Igwe, a member of the House of Representatives, was on Friday arrested in Port Harcourt with $498,100 in his car.
Police say the money was found during a stop-and-search operation along with a list of people Mr Igwe planned to give it to.
The 57-year-old is an ally of Peoples Democratic Party (PDP) presidential candidate Atiku Abubakar.
A statement by Rivers police spokesperson Grace Iringe-Koko said the lawmaker is being investigated for money laundering and attempt to buy voters ahead of the presidential and national assembly elections on Saturday.
“He was arrested by 2:45 a.m. on Friday by police officers deployed to Independent National Electoral Commission (INEC) Headquarters at Aba Road in Port Harcourt.
“The police officers, who were on stop-and-search found a cash sum of 498,100 USD inside a bag in his car meant for the elections.
“Also recovered from him was a list meant for the distribution of the money,” Iringe-Koko said.
She added that the assistant inspector-general of police in charge of elections in the state, Abuto Yero, has ordered the lawmaker’s interrogation and arraignment in court.
A video of Igwe being interrogated by security agents was circulated by the Rivers State Government on Friday morning.
In the video, Igwe said he was driving home about midnight when he was stopped by security agents along Aba Road.
He said part of the money was meant to support the PDP while the rest was his personal money.
Igwe’s arrest occurred two days after a radio and television station belonging to him was attacked by gunmen in Rivers State.
A few months ago, a fuel station belonging to the lawmaker was sealed by the Rivers State Government over alleged involvement in illegal bunkering.
Igwe said he was being victimised by Governor Nyesom Wike for supporting Atiku.
