A vocal opponent of marriage equality, Madigan said the issue should be put to a public referendum and taken out of the hands of parliamentarians.
“The definition of marriage is something that cannot be left to the whim of the parliament,” he said.
“Marriage is a cornerstone of human society pre-dating any religious or political system.
“If we can have referendums on things like local government, we deserve to have a referendum on officially defining this institution in our constitution.”
The move comes on the same day Greens legislation on recognising overseas same-sex marriages in Australia is set to be debated and voted on.
The first DLP Senator elected to the Senate since 1974, Madigan was elected on preferences in 2010, edging out Family First candidate Steve Fielding by a narrow margin.