Contributory parents, or those who can pay a $47,455 fee, need to wait on average 45 months.
But the average wait time for non-contributory parents is more than 30 years and "other family" is up to 56 years.
There are currently 49,983 non-contributory parent applications and 8,111 "other family" applications on hand.
Source: Digital Vision/Getty Images
Acting deputy secretary of Immigration and Citizenship Services Luke Mansfield told Senate Estimates some of the longer wait times were a result of migration numbers set by the government.
"The government over quite a number of years has prioritised skilled entry and had a higher component of skilled entry relative to family entry under the program," he said.
"I don't think that there's an issue with the allocation of resources internal to the department in terms of getting through those pipelines. It's more a function of the total size of the program."
'A horrific number'
Greens Senator Nick McKim, who brought up the wait times at Senate Estimates said 56 years "is a horrific number".
"So is the wait period of over 30 for years non-contributory parents," he told SBS News.
"Families are waiting years and in some cases many decades before they can be reunited to live together ... The system is broken."
CEO of the Federation of Ethnic Communities Councils (FECCA) Mohammad Al-Khafaji said: "frankly, many family members will die before they receive an answer on their visa application".
- FECCA CEO Mohammad Al-Khafaji
Many family members will die before they receive an answer.
"Unfortunately, what has been revealed in Senate Estimates is what we have known for a long time - that families are facing brutally long wait times for the processing of their family reunion visa applications," he said.
Family visas cut
Last week's budget provided further details on the government’s migration changes.
The Coalition previously announced it would reduce Australia's annual migration intake from 190,000 to 160,000 places for four years from 2019-20.
According to the budget breakdown, there will be 47,732 places in the family stream next financial year, compared to 60,750 this financial year.
"This is 13,000 families who will not be reunited this year," Senator McKim said.
"This is massive and unnecessary cut that will impact predominantly migrant families and ultimately act to keep families apart when what government should be doing is reunite as many families as possible".
While Mr Al-Khafaji said the cut meant "the federal government has ensured there will be no relief for applicants and that wait times and the backlog will continue to grow".
The Department of Home Affairs did not respond to a request for comment.