ABUJA, June 21 (Reuters) - Construction of Nigeria's 614-km (384-mile) natural gas pipeline will be completed by the first quarter of 2025, the head of state oil firm NNPC said on Friday, two years after the initial planned completion date.

Mele Kyari joined three cabinet ministers touring the project in the northern state of Kaduna and said major parts were already finished.

"Our mission is to work towards delivering it by December this year, but we are confident this project will be delivered by the first quarter of 2025," Kyari said.

In 2022, Kyari had said construction of the Ajaokuta-Kaduna-Kano (AKK) pipeline would be completed by the first quarter of 2023 after work began in June 2020.

Authorities in Nigeria, Africa's largest energy producer, say it will help generate 3.6 gigawatts of power and support gas-based industries along the route when completed.

The route of the AKK pipeline runs from Ajaokuta in central Nigeria to Kano, passing through Kaduna, all in the north of the country. (Writing by Elisha Bala-Gbogbo, Editing by Andrew Heavens)