Ralph Clissold, from the Mount Seaview Resort, about an hour from Port Macquarie, said the implications of the highway closure had been disastrous.

"It's been a catastrophic disaster for our business because we've had no business," he said.

"Most of the people for our resort business come from the west and it's been inaccessible.

"[Roads and Maritime Services] is doing the best they can at the moment, I believe, to get it open."

Mr Clissold said primary producers were also affected.

"You can't sell any stock because you can't get them mustered really, or you can't get them out if you wanted to sell stock," he said.

"It's affected every business in every way from Walcha to Wauchope."

It has been a similar story for Gary Hartas who runs the Gingers Creek Roadhouse, 116 kilometres from Port Macquarie.

"Coming up to 16 years of being here, I've never had anything like it. It's very, very quiet," he said.

"I've been trying to catch up on a lot of repairs and maintenance, within budget, but it's been a different sort of month."

Mr Hartas said he stayed to defend his property.

"I run my own power, that was one of my main things to protect, I've got a lot of money in batteries and an inverter and solar panels," he said.

"The roadhouse is fine itself. I've lost one of my cabins but the rest of it's fine, just very quiet."

Retaining walls, road surface, guard rails to be repaired

Transport for NSW said damage from the fire was "substantial".

"The highway will remain closed between Long Flat and Walcha for up to four weeks as the blazes have caused substantial damage," a spokesperson said.

"Work has begun to remove fallen trees and rocks, and to restore damaged guard rails and the road surface.

"Four retaining walls have been extensively damaged and need to be replaced to ensure the safety of road users on the Oxley Highway.

"Transport for NSW will reopen roads as soon as it is safe to do so, but our first priority is the safety of motorists and the community."

Christmas trade crucial

The road is due to reopen around Christmas, which will not come soon enough for Mr Hartas.

"From Christmas on, the next three months is probably the busiest time of the year, so I really need that to come, top up the bank account again," he said.

The general manager of Port Macquarie-Hastings Council, Craig Swift-McNair, said a special marketing campaign was being considered to promote the route when it reopens.

"There's something that will need to be done … not only has that impacted upon the tourism businesses up that way but obviously further down the valley," he said.

"I can't answer categorically what we will do but there are certainly discussions around with our tourism staff, tourism association, and Destination North Coast about what that might look like."

ABC | Story by Kerrin Thomas , Michael Cavanagh and Luke Ryan