The New South Wales government says the five-day closure of the Pacific Highway between Grafton and the Queensland border last week was unavoidable.
The inundation of the major corridor blocked trucks carrying essential supplies and emergency service reinforcements from accessing flood-affected communities on the North Coast.
But Regional Roads Minister Sam Farraway said the road network could only withstand so much amid unprecedented weather conditions.
"You've got these one-in-500, one-in-1,000-year events," he said.
The minister's response, however, offered little comfort for Kevin Weismantel, who runs a Kempsey-based truck haulage business that he said lost $20,000 last week.
Mr Weismantel recognised the ferocity of the record-breaking rain, but said the prolonged highway closure came as a surprise.
"It slowed our business right up," he said.
"We weren't expecting the highway to be closed at all, with all the upgrades."
'They've got to do something'
The $4.9 billion Pacific Highway upgrade between Woolgoolga and Ballina was the final piece in the creation of a dual-carriageway between Brisbane and Newcastle.
Completed in 2020 after 24 years, Transport for NSW promoted the road as on that provided "better flood immunity".
But Coffs Harbour-based helicopter pilot Shane Perkins said he had fielded scores of calls from families hoping to reach isolated loved ones who could not afford wait for the highway to reopen.
"It's really hard for people returning home — they haven't seen their house yet," he said.
For those unable to afford a helicopter charter, it was a frustrating wait for the northern section of the Pacific Highway to reopen.
"It's just mind-blowing that they could spend that much money and the first real test it fails," Maclean resident David Cook said.
"They've got to do something."
Mr Cook was unable to attend his daughter's wedding in Queensland because alternate routes were deemed too unsafe.
"There's got to be lessons learnt from this and they've got to be acted upon," he said.
"It's not good enough."
Criticism 'unfair, Minister says
But Mr Farraway defended the Pacific Highway's capacity during the floods.
"I think it's unfair to say after the significant investment, after a decade of building the Pacific Highway, that it's not cut the mustard," he said.
Mr Farraway said improvements could be made to the highway alongside the extensive repairs to flood-damaged roads on the Northern Rivers.
"We are not going to be able to rebuild overnight," he said.
"This is going to take years."
He said he and Transport for NSW will be prioritising developing a "five-year or multi-year plan" to rebuild damaged infrastructure.