Fuel suppliers Chevron have resumed storing diesel at Prime Port in Timaru.
The company stopped using its tanks at the port in 2010.
Competitor Z Energy says the move left it as the only supplier of diesel in South Canterbury and resulted in shortages that compromised the region's economic development.
Z says the situation in Timaru is symptomatic of what has been happening across New Zealand's fuel supply chain for decades.
The company says terminals and tanks have been progressively closed by the global companies as they redirect capital to higher returning markets around the world.