In 2014, Stats NZ found just 22 per cent of New Zealanders had food and water for three days, and a household emergency plan.
An earlier survey taken just after the Christchurch earthquakes found even fewer had an emergency kit including a torch, radio and first-aid gear.
Quakes are New Zealand's most high-profile and costly disaster, but floods are the most frequent.
According to a report last year by the Royal Society of New Zealand on the implications of climate change, floods like last month's in Edgecumbe are likely to become much more common, Block said.
Consumer's test found battery-operated radios and torches were better than wind-up for longevity and power, noting the wind-up radio in St John's kit only played for four minutes after a minute of winding.
The findings were welcomed by Wellington Region's Emergency defence Office (WREMO).
"[We agree] building your own getaway kit is the best way to go as well as making sure your household is prepared," said controller Bruce Pepperell.
"Getaway kits are just one of the many things people can do to be prepared and it is just as important having enough water, food stocks and a household plan to get through an emergency."
Getaway kits ideally should be small backpack of essential items to grab if you have to quickly evacuate your home or workplace with little or no warning. It's especially important if you will have to walk a long way to get home during an emergency or evacuate your house quickly, Pepperell said.
"The problem with a large number of commercial kits is they are expensive and heavy."
Consumer NZ chief executive Sue Chetwin said her team was able to pull together a kit for $150, which was "considerably less" than many of the pre-made packs.
"It's also likely you could put together your own kit for less than what we paid as most households are likely to have some of the items, such as a spare backpack or water bottles."
Chetwin singled out St John for having the worst kit.
"Punters who shell out $200 for this disappointing grab bag will discover it lacks basic items such as a first aid kit, food rations, drink bottle or rain poncho," she said.
Consumer NZ suggested an ideal emergency grab-bag would have a torch, radio, spare batteries, hand sanitiser, cash, photo ID and other important documents, walking shoes, warm clothes, raincoat and hat, first aid kit, prescription medicine (if required), water, snacks, rain poncho, thick gloves, dust mask, hygiene items (tissues, wet wipes, toothbrush/paste).
The Ministry of Civil Defence and Emergency Management also recommended having at least three days of water (nine litres for each person) and enough long-lasting food that doesn't need cooking to sustain each member of the household for 72 hours.
However, taking the first steps to emergency-preparedness is far more important than compiling the perfect getaway kit, Chetwin said.
Your emergency planning should cover where you will meet if you can't get home and a backup plan if you can't pick up the kids, as well as:
• The name and contact details of someone who lives out of town that your family knows to contact in case the phones go down
• A list of family and friends who may require assistance
• Plans for if you're stuck at home, including three days of food and water
• Plans for how you'll stay warm at night and cook food if there's no power
• Getaway kits if you need to leave in a hurry
To see Consumer's full report, and to compare kits, head to their website.