The company rolling out the national broadband network has rejected reports it is falling well short of its construction schedule.
The NBN has met or exceeded every key target for six quarters in a row, it insists.
Fairfax Media, quoting an internal progress report, claimed the $46 billion network was facing mounting delays and rising costs.
It said the giant infrastructure project had fallen two-thirds short of its benchmark construction timetable.
Connection costs to each house or business were also blowing out.
Not so, says NBN Co.
The company was on track to meet or exceed its full-year targets of 2.6 million homes ready for service, with about one million homes using the network, and more than $300 million in revenue.
The company's management had proven repeatedly that it could effectively monitor risks and manage those risks.
"We will not be drawn on alleged internal documents, we report quarterly and our results are audited," it said in a statement on Monday.
As at February 18, nearly 1.8 million homes could now order a service and more than 800,000 homes were already connected and using the network.
By the end of June the company was on track for nearly one in four homes to be able to order a service and by June 2018 that would grow to three in four.
The February 19 report, used by Fairfax, says the "final design" process for connections - needed before construction can start - was running far behind schedule.
While 1,402,909 premises should have been approved at the date of the report, the figure was sitting at 662,665 - 740,000 fewer than planned.
The snapshot says NBN Co has achieved 29,005 fibre-to-the-node "construction completions", while noting its internally budgeted target for this period was more than three times this at 94,273.