The banner, which displayed the climate change protest group's logo alongside the phrase 'The Tide Is Rising', was unfurled from the top of the church at around 10.40am today.
Extinction Rebellion activist, Anthony Cook, told the Leader: "Extinction Rebellion Louth is committed to raising awareness about the climate crisis and the risk to humanity in the future. Changes can be made but we must act now."
Mr Cook said the banner was in place for around quarter of an hour before it was removed, following a request from church officials.
This morning's protest comes less than two weeks after Louth Town Council supported a motion declaring a 'climate emergency', following a presentation from local Extinction Rebellion representative Ian Rushby.
More on this story as we have it.