New Zealand is a haven for a fly angler who enjoys trout fishing.

Flying from Brisbane to Christchurch on the South Island then travelling to the nearest trout water takes about the same time as a road trip from Brisbane to Ebor, including all the time spent in departure lounges and customs. And compared to Ebor, the quality of fish is simply astounding.

But with fabulous fishing, brilliant scenery and the ambience of New Zealand's South Island there is a major consideration for the traveller that will influence fishing and the return home: Didymo.

Didymo, or Didymo Geminata, is a fast growing and highly invasive algae that has spread to virtually all major South Island trout waters in the last couple of years after having been introduced from the Northern Hemisphere.

When it's freshly growing and not peeling off in large sheets, Didymo looks like a beige or pink sort of carpet stretching from bank to bank and right through the middle of the stream. Didymo thrives in running water and while a flood might shift it along it will return.

New Zealand's Fish and Game authorities are anxious to prevent the spread of Didymo. Accordingly any part of fishing tackle, clothing, waders, nets or footwear that been used in water where Didymo is present must be checked, then cleaned with 5% household detergent solution and thoroughly dried. Only a couple of minute spores of this algae is all that is needed for it to be spread to unaffected waters.

Interestingly, the Didymo infestation has not influenced the fish. Plenty of trout are still in their usual haunts but methods have needed to change. Gone are the days when the angler could hang a pair of heavy nymphs below an indicator on a rod's length level line leader, cast into the run at the pool's head and on seeing the indicator dip or stop lift the rod to feel a trout bucking on the fly.

These day that method would see a mess of Didymo wrapped all round those flies. The algae is so thick, and comes away so easily, there is no way of preventing the flies from fouling if they touch the bottom.

A change in method can still produce satisfactory results. On my trip to the South Island recently I tied a 40-50cm tippet behind a dry fly and worked a nymph through the runs for a change. I relied on a size 16 Pheasant Tail Nymph sitting below a size 10 Royal Wulff and cast this into the run, the idea being that the trout would have a look at the Wulff and then take the Nymph. This does work, and sometimes the fish even grabbed the Wulff first.

So although the Didymo looks awful the fishing is still well worth the effort. However, there are other considerations.

One direct result of Fish and Games' answer to the problem is the total banning of felt soled wading boots. These boots have been as much a part of fishing NZ rivers as rods and reels and the embargo has caused a few problems with suitable foot wear for anglers who like to wade wet.

Full sized waders, even the expensive breathable ones, are fine at daylight or after dark. But on a normal summer day with the temperature over 25º it is unbelievably hot and wading wet is a very pleasant way of cooling off.

Dedicated rubber soled boots are one answer to the felt embargo problem. These boots do inspire confidence when wading about on Didymo which is quite slippery – and when I have my expensive Nikon camera in my backpack the last thing I want is an unplanned swim.

On the recent trip I relied on Snowbee XS wading boots for my security when wading. Last year I trialled a pair of rubber sole boots and was happy enough with them but since moving to the studded rubber soled models I feel more confident in the water, they afford just that extra bit of grip.

The Snowbees cost far less than imported North American boots but give nothing away as far as ruggedness, finish, and reliability goes. You can buy a pair for less than $200, which is about half the cost of some US products.

The Snowbees are built to last, have a very wide sole for maximum grip and employ a multi faceted tread pattern, complimented by the metal studs, designed to maximize grip in streamside mud, gravel, rocks and other uneven terrain. They are also very light, and being quite flexible will not chafe or annoy ankles like very rigid boots can do.

These boots would be very useful when fishing our own trout streams, too, as their strong grip is very handy in all situations.

The full rubber sole Snowbees and XS Snowbee studded rubber sole boots in sizes 7 to 13.

At first light both here and in NZ, it can be cold with the day's heat coming later, which means a pair of thigh waders to keep legs and feet entirely dry are very handy.

I took the opportunity to try out a pair of Snowbee Nylon/PVC 210 denier thigh waders on a cool daylight excursion on the Tekapo River. I was impressed with the comfort and flexibility of them while walking about in the shallows stalking some big brown trout. The sole is a rugged and well-cleated design, which afforded a reasonable amount of grip on the Didymo, to the point where I felt confident enough to wade out fairly deep.

These light weight but quite tough waders are of a slim line design to ensure the stream's flow did not pull on them much, inspiring all important confidence when wading.

The Snowbee Nylon/PVC 210 denier thigh waders would be very handy for cooler times in the shaky isles and for a lot of general use on our own trout waters where snakes are quite often encountered on stream banks.

The Snowbees are well made with external seams, are entirely flexible, have large quick release and adjustable buckles for ease of fitting and removal. They are available in sizes from 6 to 14.

In all the Snowbee waders are an excellent product for general use.