THE full cost of Labor's original National Broadband Network plans would blow out by $29 billion and be completed three years late, the strategic review has found.
Communications Minister Malcolm Turnbull released details of the review he started 60 days ago on Thursday.
The review found the fibre-to-the-premises NBN under Labor would have cost $73 billion, $29 billion more than forecast, and not be completed until 2024.
It also found the current NBN Co corporate plan had overestimated revenues from the network by $13 billion.
While the review found the cost and timing of the original plans would blow out, Opposition communications spokesman Jason Clare challenged the review's findings.
He released an internal government analysis of the Coalition's plans, which he said revealed the new government's plans were "the wrong approach", and would not achieve the promised speeds.
Mr Turnbull has pledged download speeds of 50mbps by 2019 under the Coalition's plan, which will rely on copper connecting to fibre nodes, rather than brining the higher-speed fibre direct to all homes.
But Mr Clare said the analysis should the two stage approach - with 25mbps promised by 2016, expanding to 50mbps by 2019 - was unworkable.
He said the government's fibre-to-the-node plan would lower revenues from the network by 30% and the actual cost of fixing the existing Telstra-owned copper network, and was "unknown".
But Mr Turnbull said the review found the Labor network was "never achievable", and the results of the review would be "a crucial input into government policy".
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