The Director of Public Building in Osun State Ministry of Works, Mr Niyi Ogundiran, gave the figure at a meeting with members of the state Assembly in Osogbo on Thursday.
Ogundiran said that the concession arrangement would last for 30 years before the permanent transfer of ownership to the state government.
He said that the contract was first awarded on Oct. 14, 2012, at the cost of N 4.5bn, noting that the project was to be completed within eight months by the government and not under a concession arrangement.
Ogundiran said that the contract was later reviewed to gulp N11bn to be able to accommodate more features.
He said the state government had spent N3.6bn on the project before the concession arrangement, adding that the N3.6bn would be deducted from the N69bn contract sum.
The Permanent Secretary in the ministry, Mr Nurudeen Adeagbo, said that the concession arrangement would be to the advantage of the state.
He expressed the hope that the company would deliver a perfect job.
In his remarks, the Deputy Speaker of the Assembly, Mr Adegboye Akintunde, urged all those in charge of the project to ensure its success.
Akintunde said that Osun people were watching with keen interest to know the outcome of the arrangement.
The Chairman of the House Committee on Commerce, Co-operatives and Industries, Mr Tunde, said that the airport project was a huge investment and must be handled carefully.
Olatunji said that, if well executed, the project would facilitate economic development of the state.