A prisoner advocacy group has threatened legal action against South Australia's Department for Correctional Services after a newspaper giving information about the federal election was not distributed to prisoners.
Justice Action said 40,000 copies of the JUST US detainee newspaper were distributed to prisoners across Australia last month.
But it said South Australian authorities had refused to accept it.
"Leading legal firm Allens has given the chief executive of the Department for Correctional Services David Brown, until the close of business today to reverse his decision," Justice Action coordinator Brett Collins said on Thursday.
"If he still refuses, they will file SA Supreme Court proceedings on Friday morning arguing the constitutional right to access."
In a statement, a corrections spokesperson said the department facilitated prisoner voting in a fair, neutral, and unbiased manner and was committed to ensuring that all eligible prisoners were able to vote in the upcoming federal election.
"The department will respond to the law firm representing Justice Action accordingly," the statement said.
Mr Collins said the JUST US publication was an exercise in social inclusion and was constitutionally protected by the entitlement of political parties to communicate with citizens everywhere.
"Additionally it carries the right of people in prisons and locked hospital wards to engage in the political process and cast an informed vote," he said.