Former communications minister Stephen Conroy has conceded construction targets for the national broadband network were "overly ambitious" and overestimated the capacity of the construction industry.
In his first public speech since resigning as the communications minister when Kevin Rudd was reinstated as leader of the Labor Party, Senator Conroy also said the Liberal Party's failure to do a cost-benefit analysis of its national broadband network after calling on Labor to do so was "bullshit" and "hypocrisy".
But he admitted Labor had not realised the scale of the challenge when planning the NBN rollout.
“[The rollout targets] were always ambitious," he said on Friday at a lunch in Sydney held by the Australian Computer Society. "We wouldn't have been so aggressive if we'd known how tough it was for the company.
"So I think that that was an area where we were overly ambitious."
He added it was "undeniable" that NBN Co had failed to meet the rollout targets set for June 2013, or the targets of the first or second NBN Co corporate plan.
It was therefore "fair to say that the construction model could be legitimately criticised", he said.
Despite this, he said the project had been "well managed" if looked at as a whole and not just in terms of "how many leads have been put into homes over the last three years".
Senator Conroy said the debate on the merits of a cost-benefit analysis had been had "up hill and down dale".
"The hypocrisy of the [Liberal Party] has now shown," he said. "They're not having a cost-benefit analysis. So this [debate] is complete bullshit."
Conroy also slammed the Liberal Party in his speech — titled "Nation Building the Digital Economy" — for cutting $42 million in funding from National ICT Australia.
He said the cuts would "dramatically reduce" the number of students able to complete an information and communications technology PhD.
Senator Conroy's frank assessment of the NBN under his management came as supporters of fibre-to-the-premises broadband raised more than $26,000 for an advertising campaign in Malcolm Turnbull's electorate to try and convince the communications minister to keep Labor's NBN.