The Warehouse has its South Island distribution centre at Rolleston and Cairns indicated the train line to Timaru was a key component of the new deal, because containers would travel between Timaru and Rolleston by rail.
Cairns said the Rolleston hub would provide South Island exporters with access to the company's Timaru container terminal.
"Importers in the Christchurch area will have the option to ship through Timaru," he said.
But the Onehunga and Rolleston purchases were more one-off opportunities rather than a pattern of expansion to be repeated, he indicated.
"Really, the Canterbury purchase is replicating another MetroPort."
The deal could be a boost for Timaru's PrimePort, which was hit when Fonterra withdrew to rationalise port operations.
Cairns indicated Timaru would benefit from the Rolleston deal.
"Previously, it had been doing 80,000 20-foot containers but subsequently to losing Fonterra is down to 20,000 containers so we think there's an opportunity to target some of that business closer to Timaru and re-establish that business," Cairns said, predicting that a return to 80,000 containers was possible.
Mark Lister, head of research at Craigs Investment Partners, said the move fitted well "with POT's 'hubbing' strategy, where they have the key asset [Tauranga], and use these other smaller satellite operations as feeders into the main one".