Green groups want the regulator to bar Equinor from drilling in the Bight, concerned that oil spills in the extremely rough waters could threaten whale breeding grounds, fishing areas and pristine coastlines.
This year, the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) extended the review process to Nov. 14, but said it asked the company last week to change and resubmit its plan to drill in the Great Australian Bight.
"The opportunity to modify and resubmit does not represent a refusal or rejection of the environment plan," NOPSEMA said in a statement.
The agency said it wanted more information on oil spill risks and environmental protection, among other issues.
Equinor has 21 days to respond to Friday's request or can seek more time.
The company, which considers the Bight "a highly prospective asset", plans to start drilling exploration wells in ultra deep waters 372 km (223 miles) off the South Australian coast in late 2020.
"Equinor is focused on providing the information to NOPSEMA to support its assessment and to meet all regulatory requirements," Equinor's country manager for Australia, Jone Stangeland, said in comments emailed to Reuters.
He said the company remains committed to gaining approval to drill one exploration well in the Bight in late 2020 to early 2021 and would continue to engage with stakeholders and local communities about its plans.
Environmental group Greenpeace said it hoped Equinor would follow BP Plc in abandoning the Bight.
"The communities of the Bight, traditional owners and the thousands of people in the seafood and tourism industries whose livelihoods depend on healthy oceans will never accept oil drilling in the Bight," Greenpeace Australia Pacific senior campaigner Nathaniel Pelle said in a statement.
By Sonali Paul