| Name | Character | Episodes |
|---|---|---|
| Anna Torv | Harriet Dunkley | 12 |
| Marcus Graham | Andrew Griffiths | 12 |
| Aleks Mikic | Thomas Maher | 12 |
| Sacha Horler | Ludie Sypek | 10 |
| Jacki Weaver | Catriona Bailey | 9 |
| Benedict Hardie | Declan Boyd | 6 |
| Damon Herriman | Kim Gordon | 6 |
| Alan Dale | Martin Toohey | 6 |
| Kate Mulvany | Ronnie | 6 |
| Danielle Cormack | Karen Koutoufides | 6 |
| Louisa Mignone | Mina Almasi | 6 |
| Alex Dimitriades | Charles Dancer | 6 |
| Joel Tobeck | Jim Hellier | 6 |
| Don Hany | Ewan Garrity | 6 |
| Dan Wyllie | Mal Paxton | 6 |
| Benedict Samuel | Felix Crawford | 6 |
| Laura Gordon | Caroline Treloar | 6 |
| Eugenia Yuan | Weng Meigui | 6 |
| Rob Collins | Joseph Sullivan | 6 |
| Miranda Tapsell | Sasha Rose | 6 |
| Andrew McFarlane | Lockwood | 6 |
| Ferdinand Hoang | Ambassador Dhao | 6 |
| Matt Zeremes | Sean Brimmer | 6 |
| David Roberts | General McAuliffe | 6 |
| Alice Chaston | Sabine Hobbs | 6 |
| Sean Taylor | Wheeler | 6 |
| Huw Higginson | Reardon | 6 |
| Brenna Harding | Cassie | 5 |
| Mekhi Phifer | Ambassador Moreton | 5 |
| Christopher Kirby | Kip Buchanan | 5 |
| Anni Finsterer | Rear Admiral Hartzig | 5 |
| Laura Brent | Dr. Crick | 5 |
| Michael Denkha | Michael Lavelle | 5 |
| Renee Lim | Helen Wu | 4 |
| Dalip Sondhi | Yasir Younis | 3 |
| Ron Falk | Les Gordon | 2 |
| Doris Younane | Jane | 1 |
| Barbara Gouskos | Nadine Almasi | 1 |