The Routeburn Flats hut was about 45 per cent booked.
On both tracks, about 80 per cent of bookings went to Kiwis, and 20 per cent to international visitors.
Several trampers posted on social media to express their disappointment at missing out on the Milford Track.
Auckland man, Keith Mitchell, who said he had been trying to book a spot on the Milford Track for five years, suggested it was time to rethink the booking system.
"In a way the booking system for the Milford Track is not unlike the original MIQ booking system," Mitchell said.
"Surely a queue with names carried forward or a lottery system might be better," he said.
Department of Conservation booking services manager Ross Shearer said there were several factors driving demand.
"Kiwis are really keen to get out there and enjoy the wilderness," he said.
"Part of [the demand] is overseas travel being less accessible ... part of it is they're just incredibly beautiful walks ... and people are realising that."
Shearer said the booking system was "powerful" but DoC was in discussions about improving the system.
"Maybe like the MIQ system where you went into a lobby or something, or went into a queue, we could look at something like that.
"But it doesn't really change the system, there's still going to be those that are quick on their fingers," Shearer said.
He encouraged trampers to explore the nine other Great Walks available and said if bookings were unavailable for huts, there might still be campsites available.
The Great Walks season celebrated its 30th anniversary this year.