Former Black Caps all-rounder Chris Cairns has enjoyed his "best day of rehab yet" as he continues to recover from the life-threatening injuries he suffered four months ago.

He subsequently suffered a spinal stroke, resulting in leg paralysis, and is undergoing daily rehabilitation at a specialist hospital in Canberra.

That rehab routine involves five hours of work in a gym, six days per week, as he attempts to strengthen muscles that have been effectively separated from his control for months now.

And today Cairns was able to use a hydrotherapy pool for the first time, standing unaided in the water in an experience he described as "the most free I've ever felt".

Earlier this month Cairns that his elite sport background was helping him deal with his new reality.

"Having rehabbed during a sporting career you understand mental discipline is required," he said. "I know that some people in rehab facilities don't have that background and they struggle with motivation to get up every day. They are not seeing many gains. Having that background and single mindedness will play a role in helping me get to where I want to get to.

"It would be quite easy to give up and accept, maybe this is it. I will try and squeeze everything I can in over the next 12-24 months. Having been in a career when bones and muscles take six weeks to repair, there is no timeline here. I may get a flicker in three months in one muscle but it may take nine months.

"Your muscles atrophy over time and so then that takes time to build back up. It is one thing getting nerves to turn back on but then you have to build the muscle back up so you can stand and then walk.

"I don't know if I will ever walk again and I have made my peace with that," he says. "It is now about understanding I can lead a full and enjoyable life in a wheelchair but at the same time knowing it will be different."