NBN Co chief Bill Morrow will step down this year.

Mr Morrow has been in the CEO’s role since April 2014.

“I believe that as the company prepares to confront the new challenges ahead, this is the right time to hand over the reins for the next phase of this incredible project and for me to plan for the next step in my career,” he said.

He says NBN Co is on track to make a financial return, eventually.

The company says 80 per cent of Australia will be able to connect to the NBN by the end of 2018.

Former communications minister and now Prime Minister Malcolm Turnbull thanked Mr Morrow for doing an “amazing job”.

“He's been a great CEO. He's done a great job and what he's doing, very responsibly, is giving plenty of notice of his departure so that they can look around for a new CEO,” he said.

Mr Turnbull says problems with the NBN are caused by the way the project was designed.

“I appointed [Mr Morrow] chief executive after we came into government in 2013,” Mr Turnbull said.

“The National Broadband Network project was a complete train wreck that we inherited from the Labor Party and it was really the biggest turnaround, I would think, in Australian history.

“Bill is a great leader. He's turned the project around. It is now about two-thirds finished and it's well on track to be completed by 2020.”