Chevron appears to be bracing for another cost blowout at its $52 billion Gorgon liquefied natural gas venture in Western Australia, potentially delaying an ­expansion of the country’s biggest resources project.

Chief financial officer Pat Yarrington told investors in the United States on Friday that while productivity on the construction project on Barrow Island had increased, some areas “still need to improve", and heavy rain in June had also taken a toll. She said Chevron was in the middle of finalising its budget for the year, “and should there be any reviews during that that suggest a material change, other than what we have said previously, we will certainly bring that to your attention".