Ms Prasad said the danger period for a cyclone crossing into Australia would be between Friday and Sunday.
There was a small chance the cyclone could form by Thursday, she said.
She added cyclones are highly unpredictable and it is difficult to say whether a cyclone will form.
She advised people in the Top End to ensure they have a cyclone kit ready, with a radio, batteries, essential clothes and food for three days, and the location of the nearest cyclone shelter.
"It is the cyclone season and it is going to continue until April and a cyclone can occur at any time,'' Ms Prasad said.
The northern part of Australia typically experiences two to three cyclones each season, which lasts until April, but this year forecasters are expecting slightly more than average.
On Christmas Eve in 1974, Cyclone Tracy devastated much of Darwin and killed 71 people.
- AAP