“What an incredible human being he was. You could not miss his positive spirit,” Lieutenant-General Arno Lamoer said in a statement.
He trained a number of police members in the airwing department.
His helicopter crashed while he was fighting a blaze at the Cape Point Nature Reserve on Sunday.
Lamoer conveyed condolences to Marais’ wife, family, and colleagues.
“He will be sorely missed. On behalf of the SA Police Service family we say may his soul rest in peace,” Lamoer said.
The blaze started a week ago and was contained, but later flared up again in Muizenberg, above Boyes Drive, fanned by strong winds.
It spread to Ou Kaapse Weg, Chapman’s Peak, Hout Bay, and Tokai.
Another city fire-fighter sustained burn wounds and 52 frail-care residents from a Noordhoek retirement village were treated for smoke inhalation.
At least 500 people had been evacuated since the fire began in Muizenberg and around 2000 had helped to fight the blaze.