Secret documents from 2013 show the coalition government deceived Australians about the cost of the National Broadband Network designed by Labor, deputy chair of parliament's NBN committee Susan Templeman said.
Ms Templeman said the government knew "all along" that rolling out fibre to the premises, as Labor had planned, was going to cost up to $15 billion less than they were saying publicly.
"This was a deliberate deception by Tony Abbott, by Malcolm Turnbull, and the assistant minister at the time Paul Fletcher," the Labor MP told reporters in Canberra.
"They did not disclose these figures and that's left people in my electorate and across the country with a legacy of substandard NBN."
Within a couple of kilometres radius in the Hawkesbury and Blue Mountains, she said some people are on fibre to the premises while others have fibre to the curb or fibre to the node, some are on satellite and others are on wireless.
"A lot of people say forget the NBN, I'm sticking to 4G, if they have access to that. A lot of people say to me forget satellite, I'm going to stick with ADSL. Now that's an appalling state for Australia to be in after so much investment," she said.
"This is a system that has let down people."
Ms Templeman said the headline figure in the secret document was $10 billion, but the report says when you look at the cumulative debt, that's another $5 to $6 billion to build a network for "an unequal service".
A spokesman for the Communications Minister Paul Fletcher backed in the "multi-technology model", telling AAP it had been used to deliver the project efficiently and economically.
"Labor's ill-conceived plan would have cost billions more and taken years longer to deliver - leaving millions of Australian households and businesses stranded and unable to connect when COVID-19 hit," he said.
But Ms Templeman said the difference between having fibre to the premises and being allowed to connect to a satellite was the difference between being able to effectively run a business from home.
Australian Associated Press