Officials from the Department of Primary Industries have resolved 6584 properties, with just four remaining to be resolved. Eight properties are formally listed as "suspect".
The state hopes to be officially free of equine flu late in March.
NSW chief veterinary officer Bruce Christie said the move to white zoning - which covers 91% of the state - meant NSW was one step closer to the goal of being free of equine influenza by the end of March. Officials also moved some red zones to amber in the zoning revamp.
Mr Christie described the changes as significant, allowing thousands of horses locked down since August 25, or unable to move interstate, to begin moving again.
"And horses within the new white zone can now be moved over state borders more easily following the downgrading of the green zone infection risk to the same level as interstate EI free areas.
"With no new EI infections detected this year and only four infected properties remaining in NSW, widespread testing is continuing to prove we haven't missed anything and that we are approaching freedom."
As part of the NSW Equine Influenza Protection Plan, the risk in some amber zone areas in the State's north-west, northern tablelands and lower north coast have been downgraded and those areas moved into the new white zone.
"Now that the white areas of NSW are free of EI, authorities in EI-free states will accept interstate horse movements from this zone without all the quarantine and testing requirements of the past," he said.
"Importantly, the white zone also demonstrates internationally that we have EI under control and that it is not widespread.
"In addition, the degree of risk in previous red zones at Armidale and Grenfell has been scaled back to amber following confirmation that horse flu has burnt out in these areas.
"A total of 91 percent of NSW is now in the white zone, the amber zone has been reduced from 9 percent of the state to just 4 percent and red zone has been cut to less than 2 percent."
Mr Christie stressed that until EI freedom status was achieved throughout NSW it remained vital for all horse owners to report sick horses, enforce bio-security and abide by movement restrictions.
"It will also remain important for some time for horse movements to be recorded in the highly unlikely event that another infection is detected," he said.
"For this reason Travelling Horse Statements will be required for the foreseeable future for movements in the white zone.
"Similar documentation will also be required outside NSW for horses crossing the border."