The federal government has acknowledged the $4.5 billion upgrade of the National Broadband Network will make the company more attractive to a buyer but says any privatisation is still several years away.

While Communications Minister Paul Fletcher and NBN Co chief executive officer Stephen Rue declined to estimate the value of the company – either in its current state, or by 2023 when the upgrade is due for completion – the prospect of eventual privatisation was factored into government deliberations when approving NBN Co's corporate plan.