Nigerian oil company Oando said on Monday it had settled a squabble with a key shareholder and was working on resolving remaining shareholder disputes and getting a suspension of its shares lifted.

The company said it has addressed issues raised by Dahiru Mangal, ending a drawn-out conflict, and would consider appointing one of his representatives to its board.

Mangal, who owns more than 10% of Oando's shares, petitioned Nigeria's Securities and Exchange Commission (SEC) last year, alleging financial mismanagement at the firm.

The SEC ordered a forensic audit into the oil company's shareholding structure, citing concerns about possible insider trading.

The conflict led to the suspension of Oando's shares on the Lagos and Johannesburg stock exchanges. They have been suspended at 5.99 naira each for more than three months.

Mangal said in Oando's statement that, after receiving clarifications from Oando's management, he had withdrawn his petition to the SEC.

A spokesperson for Oando said that the SEC has not said whether it would call off the audit now that the dispute with Mangal had been settled, adding that a second petition from an indirect shareholder was still pending with the regulator.

Ansbury, an investment vehicle with an indirect shareholding in Oando, had also filed a petition with the SEC alleging abuse of corporate governance and financial mismanagement.

The SEC was not immediately available for comment.

The Oando spokesperson said the company was now focusing on settling remaining disputes.

"In 2018 we are trying to resolve all issues so that we focus on running the business and get our share price lifted. The price of oil is going back up and this needs to be reflected on our share price," she said.

Oando has sold off some assets in the downstream sector and is focusing on businesses that generate dollars, she said, adding that the firm has paid down over half its debt since its bought ConocoPhillips' Nigerian assets in 2014 to 209-billion naira ($685-million) as of the third quarter last year.

The settlement with Mangal was reached thanks to mediation by the Emir of Kano, Muhammadu Sanusi II, a former central bank governor and a respected religious leader in northern Nigeria.

In October, the SEC said it had carried out a comprehensive review of Oando after it received the petitions and found related party transactions were not conducted at arm's length and that there were discrepancies in its ownership structure. The SEC has said a team of auditors, lawyers, stockbrokers and share registrars would conduct a forensic audit on Oando to ensure independence.

The company spokesperson said auditors had not contacted Oando but that it has been providing information to the SEC.

A company source told Reuters last year the petitions centred around the ownership of some Oando shares bought through an investment vehicle at the time the company bought ConocoPhillips' Nigerian business for $1.65-billion in 2014. Oando made the acquisition to add oil exploration and production to its petroleum product retailing businesses. But high financing costs coupled with lower oil prices hit profits.