The injury-prone Oram returned home after the first Test of the recent Bangladesh series complaining off stiffness and pain.
An MRI scan cleared him of serious injury but he is not expected to be fully fit until next month's West Indies tour of New Zealand, Cricket New Zealand said in a statement
Oram told Radio Sport he could have pushed to make the Australian tour but it was not worth the risk.
"We could have tested it, trialled it, maybe even gone and had a fitness test to see if I could have made it," he said.
"But the worrying thing was that it isn't 100 percent at the moment, and if we made it even worse then it meant the West Indies series was probably in jeopardy."
Oram, who was sidelined for most of 2005 with a back problem, also admitted he had considered giving up bowling and concentrating on his batting, particularly with an eye on the 2011 World Cup.
"If I want longevity in the game, I don't think I can go along doing what I'm doing now and hope to play for another four or five or six years.
"I just can't see that happening."
The 30-year-old Oram has a Test batting average of 37.04 and has taken 60 wickets at 31.18.
In one-day internationals his batting average is 25.50 and he has taken 128 wickets at 30.14.