'Iron Man' still Aussie box office No.1

Superhero blockbuster Iron Man has remained at the top of the Australian box office for the third week.

The movie, starring Robert Downey Jr. as Tony Stark, holds off Ashton Kutcher comedy What Happens In Vegas, which sticks at two.

Robert Luketic's real-life drama 21 is a new entry at three, while horror movie Shutter lands at five.

Then She Found Me - written by, directed by and starring Helen Hunt - leaps nine places to six.

The top ten movies in full:

1. (1) Iron Man - $2,392,351
2. (2) What Happens in Vegas - $1,932,037
3. (-) 21 - $1,473,409
4. (3) Made of Honour - $599,816
5. (-) Shutter - $407,174
6. (15) Then She Found Me - $309,450
7 (4) Forgetting Sarah Marshall - $231,528
8. (5) The Painted Veil - $225,075
9. (6) Miss Pettigrew Lives for a Day - $171,577
10. (7) Die Fälscher (The Counterfeiters) - $162,310