David Morse said that estimate doesn't include the firefighting costs covered by the Halifax Regional Municipality.
More than 130 firefighters were on the ground near Porters Lake on Saturday in addition to the helicopters and water bombers called in by the Natural Resources Department.
"These big water bombers literally cost thousands of dollars every hour to have in the air," Morse said.
"At one point in time we actually had 13 aircraft in the air simultaneously."
Morse said his department will foot the bill for the aircraft, including two water bombers called in from Newfoundland and Quebec.
He said borrowing the water bombers worked well and the province wouldn't save money by getting its own water bomber, which would cost about $28 million. The total doesn't include the costs of hiring pilots and maintaining the aircraft.
Morse said the province has similar borrowing agreements with several provinces and U.S. states, having called in aircraft 10 times over the past decade.
The minister said the province can ask the federal government for help with the costs if the bill totals over $1 million in the end.
However, Premier Rodney MacDonald said the province is prepared to foot the bill.
"We know that we're going to have to absorb the cost in emergency-type situations, and the government will be able to live within its means in doing so," MacDonald said.