Telstra management has directly contradicted claims by its workforce that the telco's copper network is in disrepair.
Appearing before a Senate Select Committee into the National Broadband Network on Tuesday, the company's director of government relations, James Shaw, also declined to guarantee an audit of the network would be conducted before its use as part of the NBN.
"They are matters that will be discussed in the context of negotiations," Mr Shaw said, responding to questions by Greens Senator Scott Ludlam.
The exchange followed last week's release of a strategic review into the NBN presented by Communications Minister Malcolm Turnbull, key parts of which had been blacked out - including an estimation of the cost of Telstra's copper network.
The Senate committee heard two weeks ago from Telstra staff, who said 70 per cent of the network's joiners were being patched up with plastic bags, gaffer tape and gel to protect parts of the network contained in pits.
Mr Shaw on Tuesday rejected the figure.
"Do you want to hazard a statistic?" Senator Ludlam asked.
"I can't," Mr Shaw said.
Earlier, NBN Co executive chairman Dr Ziggy Switkowski told the committee he would not "buy into" questions asking him to guarantee internet speeds.
"One of the problems I have found in reviewing the past is there has been a too-quick take-up of words like `guarantee'," Mr Switkowski said.
"It's clear after four years of the NBN, guarantees have lost currency."
Committee chair Senator Stephen Conroy repeatedly asked Mr Switkowski if the roll-out was being deliberately slowed, prompting Liberal Senator Anne Ruston to accuse him of trying to verbal the former Telstra CEO.
"We have inherited a somewhat dissatisfied group of partners who are dissatisfied with us, who have slowed deployments," Mr Switkowski said later.
"There's no change in the current strategy. We are rolling out fibre to the premises where we can.
"We have a machine ... that is running at four or five thousand (homes) a week, which it was during Senator Conroy's time."
The NBN review released by Mr Turnbull on Thursday found that under Labor's plans, the rollout would miss its 2021 target by three years and cost $73 billion - up from $43 billion - to complete.
Mr Switkowski said the rollout had been largely scattered, and involved many contractors doing sub-critical work.
The committee heard divisions within NBN Co had been providing different sets of figures on the same subject.
The review also found the government would not be able to meet its pledge of delivering 25 Mbps to all Australians by 2016, and its NBN plans would cost 40 per cent more than the $29.5 billion estimated in April.
Mr Turnbull said the coalition remained committed to limiting its equity investment in NBN Co to $29.5 billion, with the excess cost to be made up through debt.
