A concerning time for Southland's Tiwai aluminium smelter employees

Rio Tinto, the owner of the country's largest electricity consumer, is considering closure of the Bluff plant as part of a strategic review.

E Tu Union Southland organiser, Trevor Hobbs, says it's tough news for employees.

He says it's unsettling working in an environment where you don't know if you'll have a job this time next week.