Refining New Zealand says its hydrocracker unit is now back in action and the prolonged shutdown should cost it less than previously expected.
It is now expecting a one-off impact on processing fee revenue of between $US7 to $US9 million.
Previously, the company had estimated the shutdown would reduce its processing fee revenue by between $US10 to $US15 million.
The hydrocracker has been out of action since early March and having it offline has restricted the company's ability to upgrade lower-cost feedstock into high value products.
Now, it says good operational performance in parts of the refinery not affected by the shutdown, and the sale of excess hydrocracker feed at higher than expected prices, will limit the financial impact.