Police said the suspect was charged with one count of arson causing death and intentionally lighting a wildfire near the town of Churchill that killed at least 21 people. It was one of hundreds of fires that raged through southeastern Victoria state Feb. 7, leaving 7,000 people homeless and razing entire towns.
The suspect also was charged with possessing child pornography.
The disaster's official death toll is 181, but efforts to find and identify victims were continuing and officials expected the final tally to exceed 200. More than 1,800 homes and 1,500 square miles of forests and farms were burned.
The suspect's identity was being kept secret for his own safety, Victoria Police Assistant Commissioner Dannye Moloney told a news conference. He was brought to the state capital of Melbourne from Morwell, 75 miles to the east and near the the town of Churchill.
"He has been moved from that area and moved to the Melbourne metropolitan area for security reasons," Moloney said.
Australian Broadcasting Corp. reported from Morwell that the suspect was formally charged in the town's magistrate's court, but that he did not appear. He was ordered to be held in custody and to undergo psychiatric evaluation, the broadcaster said.
Police said in a statement that Magistrate Clive Allsop banned publication of any details or photographs of the man that could identify him. Another court hearing was scheduled for Monday.
If found guilty, the man faces a maximum penalty of 25 years in prison for the deadly arson charge, and a maximum of 15 years on the second arson charge.
Police have said they believe foul play was the cause of at least two of the deadly blazes, including the Churchill fire. Those suspicions disgusted the country and prompted Prime Minister Kevin Rudd to describe the fires as possible mass murder.
Ruth Halyburton, whose home in the town of Marysville was burned to the ground, said Friday she could not comprehend why anyone would want to light wildfires.
"Words can't describe how I feel about them," Halyburton told The Associated Press at a relief center in nearby Alexandra. "I'm a Christian, but I don't think too kindly of people if they go light a match and destroy people's property and lives. They don't have a brain in their head."
Marysville, a town of some 500 people, was almost completely destroyed Saturday by one of the fires - but not the Churchill blaze.
Firefighters still struggled to contain about a dozen blazes and one of them flared up Friday and menaced the town of Healesville, coming within less than a mile (1 kilometer) and sending embers dropping like rain over houses.
The threat was downgraded after a few hours, but it served as a reminder that the disaster may not be over yet.
"You can't see anything. All you can see is smoke, and you can't even see where the fire is actually coming from," plant nursery owner John Stanhope told ABC radio from Healesville during the flare-up. "It's just thick smoke everywhere and everyone is just very much on edge."
Firefighters raced to take advantage of cooler weather, rain and lighter winds and lit controlled burns Friday in efforts to prevent further breakouts.
The catastrophe's scale became clearer Friday. Officials raised the tally of destroyed homes by 762 to 1,831, and the number of people left homeless or who fled their homes and have not returned was raised by 2,000 to 7,000.
Officials said the nation had pledged more than 75 million Australian dollars ($50 million) in donations to various charities for survivors. Rudd ordered military bases to be opened to house some of the homeless.
The disaster increased the urgency for a nationwide fire warning system, which has been snarled for years in bickering between state and federal officials.
"I am determined to see this thing implemented across the nation," Rudd said late Thursday. "If it means cracking heads to ensure it happens we'll do that."
Officials partly blamed the dramatic death toll on the number of people who appeared to have waited until they saw the fast-moving blazes coming before trying to flee. Many bodies were found in burned-out cars.