From early next year, Countdown supermarkets will be rebranded as Woolworths.

It comes as Countdown announces its long-term plan to deliver the "best supermarket experiences" for Kiwis.

An investment of more than $400 million over the next three years would see the brand change, a focus on older stores across Aotearoa, and a new loyalty programme called Everyday Rewards.

Security and upskilling staff will also be invested in, costing $45m.

A new distribution centre for fruit and vegetables will also open in Christchurch, akin to the one in Auckland which opened last year.

Managing director of Countdown and Woolworths Group New Zealand Spencer Sonn said the supermarket chain had been working hard to become a better business and do more for its customers.

"Having had the privilege of leading the New Zealand team for over two years now, I know there's a lot that people love about what we do, and none of that will be going away. But our ambition is to be the best and to do this we know we need to be a better place to shop, better to work for and all-round better for Aotearoa's tomorrow.

"We are proud to be part of New Zealand communities and with this transformation our customers can expect to see more value, better ways to shop in-store and online, sustained investment in our charity partnerships and for us to lead in sustainability."

Sonn said it was changing for the better - and changing its name to Woolworths was part of that.

"In the coming months and years, you're going to see us bringing the best of the Woolworths brand across the Tasman and equally sharing the best of what we have here with the broader Woolworths Group."

Woolworths Group chief executive Brad Banducci said Woolworths had a "long history" in New Zealand with its first store opening in Wellington in 1929.

There is now 194 Countdown stores across the country with 22,000 employees.

"I'm excited by today's announcement and what it means for our continued commitment to New Zealand and its ongoing importance to Woolworths Group," Banducci said.

"The next stage of our transformation and the rebranding of our stores to Woolworths Supermarkets New Zealand, means we're doubling down on our trans-Tasman connection to bring the very best to our Kiwi customers. That includes a refreshed loyalty programme focused on providing more value and a materially improved fresh offer."

Woolworths signage will start popping up at Countdown stores in the coming months, with the "entire network" planned for the next couple of years.

Main image (Supplied): Countdown Richmond with the new Woolworths branding.