The track gives walkers and mountain bikers great views of Lakes Wanaka and Hawea and the Southern Alps.
Chairman Paul Cunningham said the association was waiting on costing for the installation and was checking with Land Information New Zealand to make sure it was all legal.
If deemed reasonable, "we'll put it in there".
The association would cover the cost of running the facility until the council took over, he said.
Association committee member Doug Brenssell said the track, which is about a six-hour return trip, had rapidly increased in popularity in recent years.
"It's getting popular. On average, there's 25 cars a day in the car park, so a toilet's definitely needed."
While scouting the area, Mr Brenssell spoke to people on the trail who said their reason for hiking the track was because the Roys Peak track had become "too popular".
He said the portable toilet would be sited near the start of the track, so plumbers could access it easily.
A permanent toilet further up the track was "definitely" planned for the "very near future", he said, although he was unsure of the cost or where it would be located.
