The NBN would remain publicly-owned under proposed laws as Labor attempts to draw the coalition into a privatisation fight.
Communications Minister Michelle Rowland introduced legislation to parliament on Wednesday to keep the $51 billion high-speed network in public hands.
"It remains vital that the ongoing mission and focus of the NBN to deliver affordable, accessible, high-speed broadband to all Australians be guided by the public interest rather than the commercial interests of a privileged view," she said.
Ms Rowland said more than 8.5 million customers would be worse off if the network was privatised.
Her department has estimated the network's worth at less than $20 billion.
She challenged the coalition to reveal whether it would privatise the NBN.
Victorian Liberal MP Zoe McKenzie said she had never heard her party planned to sell it off.
"It has always been in the contemplation that it would be privatised when the time is right," she told Sky News.
"There was no proposal for it to happen now."
Prime Minister Anthony Albanese said the government would ensure regional and rural communities would be looked after, as NBN access was a matter of equity.
"The National Broadband Network is a vital national asset and it delivers an essential public service," he said.
Opposition communications spokesman David Coleman said the coalition would form a view on the legislation once it had been briefed and could review it.
"But what this is about ... is an attempt to distract from the catastrophic failures from this government relating to many things, including the NBN," he said.
In August, NBN Co's 2024 financial results showed its revenue for the year increased four per cent to $5.5 billion and earnings rose to $3.9 billion.
The federal government in 2023 announced a $2.4 billion investment in the network to fund internet upgrades for 1.5 million homes.
Greens communications spokeswoman Sarah Hanson-Young said her party would seek a Senate inquiry to examine the legislation in detail.
"The NBN is a critical piece of infrastructure that should be affordable and accessible for everyone and it's why the Greens have long fought to protect the NBN from privatisation," she said.
The Communication Workers Union, which represents NBN staff, hailed the move to keep Australia's "digital backbone" in public hands.
