Home Affairs Minister Jason Clare said aerial surveillance of a debris field of wood and life-jackets had spotted 13 bodies and a full-scale hunt was under way for survivors.
"This is a search and rescue, trying to find people alive," Clare told reporters, describing the incident as "another terrible tragedy, another terrible reminder how dangerous these journeys are".
When the drifting boat was first spotted by a border protection aircraft on Wednesday, Clare said officials "identified approximately 55 people on the deck of the vessel, mostly adult men but also a small number of women and children".
The Warramunga arrived on site to find wood and life jackets floating, with the first body sighted late on Friday and another 12 found by Sunday morning.
Rear Admiral David Johnston, head of border protection, said the "complex and time-consuming" task of recovering bodies would wait until the search for survivors was exhausted.
"We believe from (medical) advice that we are still in the window where survivability is possible," Johnston said.
He added that Indonesia's maritime authority Basarnas was "certainly aware of the incident" but was caught up with a number of other vessels closer to the Indonesian coastline.
HMAS Warramunga had also been diverted to assist another suspected people-smuggling boat off Christmas Island, which issued a distress call to Australian police overnight, Clare said.
Australia is struggling with a record influx of asylum-seekers arriving by boat from Indonesia and Sri Lanka, with numbers expected to top 25,000 in the 12 months to June 30 despite punitive policies banishing refugees to the remote Pacific.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
