Ours are the reverse ... stage four is the most restrictive.
Stage four (for Melbourne people) involves:
Curfew on Melbourne residents between 8pm and 5am (now changed to 9pm and 5am)
Leaving house only for one of four reasons - "shopping for food and essential items, care and caregiving, daily exercise and work. Employers must support you to work from home if you can work from home" ... or "are at risk of family violence or to apply for an intervention order, and to attend court or a police station" or for medical services
Shopping only 5km from home, or if further, the nearest supermarket
Only one person to go shopping
No home visitors except for a person that you are in an intimate relationship with (now also allows single persons to have another single person visit)
Exercising outside for 1 hour each day within 5km from home (now changed to 2 hours per day)
Can exercise with one person from same household
Masks required whenever leaving home, except for children under 12
General retail shops closed
Stage three (for the rest of Victoria):
Bascially the same, except distance is not limited to 5km, retail is open with density requirements, no curfew, no shopping persons limit, no limit on how many times you go out, and you can exercise with another person and a personal trainer as well
All other states are in stage one: no restrictions other than social distancing, sanitising, borders closed to some states (I think all are closed to NSW and Vic, with WA having borders still closed to all states).
Melbourne stage 4 restrictions and Covid lockdown rules explained
Regional Victoria stage 3 coronavirus restrictions and lockdown rules explained