AA Petrolwatch spokesman Mark Stockdale said the latest acquisition could be good news "if indeed Caltex Australia do plan to expand the Gull network".
"That could just help support, giving them greater options in terms of sourcing fuel and potentially benefits from the economies of scale that come with that."
Gull was well known for delivering lower fuel prices, Stockdale said.
"It remains to be seen what this [deal] actually means but Caltex Australia's purchase of Gull in the first place potentially could be good news for Kiwi motorists if it means that Gull have the funding of a large parent company to expand," he said.
Gull New Zealand general manager Dave Bodger said the company had opened three sites prior to Christmas and had three more under construction, which would give it up to 87 branded stations.
There was also a large number of potential sites in various stages of progress.
"Our parent has bought us because we're a growing business and we've been growing for the last 12 years and are continuing to grow regardless of what other things might be purchased by our parent around the world," Bodger said.
"There's another division being purchased somewhere else, that's great but we were on the growth path to begin with."
Gull does not have any sites in Wellington or the South Island.
"We've never quite got to Wellington but I think over the next two or three years I think we'll find the right piece of land down there."
There were no immediate plans to expand to the South Island "but it's always on our alert list".
There was plenty of room for expansion in the North Island, Bodger said.