I'm not sure they are - have seen a few posts here and there asking for details, with no response.
I have them on my 4.6m tinny and they work great - but I only use them when I have newbies on the boat as my regular crew understands the tippy nature of smaller boats. They were invaluable though when I first got the boat.
I'm unsure if you'd be able to fit onto a pontoon as there are brackets that need to be screwed/rivetted to the side of the boat for the Aqualisers to sit during travel - this would involve putting holes into your pontoons.
I am also somewhat surprised that a pontoon boat would feel tippy and unstable - the effective shape of the Aqualisers, in conjunction with the hull, is similar to a large gullwing shape and I'm surprised the pontoons aren't achieving that already.
This is the other system I've found in Australia - https://boatcollar.com.au/ - have no idea if available here in NZ.