Communications Minister Stephen Conroy and Finance Minister Penny Wong have announced that Ten Network director Siobhan McKenna will be the chair of NBN Co, after Harrison Young decided not to recontest the position.

McKenna, who is currently a non-executive director of NBN Co, has been on the board of Ten since mid last year, and is a managing partner of Illyria Pty Ltd, an investment company started by Lachlan Murdoch, son of media magnate Ruper Murdoch. McKenna was also a partner at McKinsey & Company, the firm behind the National Broadband Network (NBN) implementation study .

Wong said McKenna will bring her lengthy experience to the job.

"McKenna brings extensive experience to the role and her expertise will help guide NBN Co as it rolls out the NBN," Wong said.

Conroy thanked Young for his time with NBN Co.

"Young has been integral to establishing the commercial arrangements that provide a strong foundation for the company and the volume rollout of the NBN."

Young said it had been a privilege to serve as the chairman of NBN Co.

"I wish Siobhan, Mike Quigley and all my colleagues at the company the very best as they take this important initiative forward."

Young was appointed by the government from the Commonwealth Bank in March 2010 . In his last major public appearance as the NBN Co chairman in September 2012 , he warned Shadow Communications Minister Malcolm Turnbull that his fibre-to-the-node (FttN) policy may be more expensive than the current NBN plan, due to having to renegotiate with Telstra for access to its copper access network.

The announcement comes ahead of a press conference with NBN Co at 4pm AEDST, where it is expected that the company will significantly decrease its target for premises passed by fibre as of June 30 this year.

It also comes as the leadership of the Australian government by Prime Minister Julia Gillard is in question, with a Federal Labor ballot for the leader and deputy leader position to be held at 4.30pm AEDST.