A short soak in water and baking soda will help extend the life of fresh raspberries, says Waikato berry grower Jay Malloy.

After rinsing the berries, he recommends soaking them in a small amount of this mixture for a couple of minutes, straining them then storing them in a ziplock bag in the fridge.

"There's a good chance that your berries are going to be in a lot better condition than if they were just put in on their own," Jay tells Jesse Mulligan.

Jay is the managing director of Kaipaki Berries, which produces strawberries, raspberries and blackberries.

He says raspberries are so expensive this year because flooding in Hawke's Bay earlier this year destroyed so many plants.

"It wiped out a large majority of the tunnel raspberry supply in New Zealand, so what that means is there's just very little supply of raspberries at this time, probably about 70 percent back."

When it comes to strawberries, prices are high due to wild weather ruining a third of New Zealand's strawberry plants back in June.

He would like supermarkets to help the situation by "getting a bit tighter" on their profit margins for Kiwi's favourite summer berry.

"What customers are paying isn't exactly close to what we're getting in return from the supermarket."

When buying strawberries, Jay recommends being careful to choose "the good ones" from the shelf.

"I'd just be a bit careful with which ones you're picking up at the supermarket.'