The area close to Halifax has seen more than 500mm of rain since 1 March.
Andrew Gilberto uploaded the video of the spider, which was spotted close to Halifax's Spar supermarket.
Channel 9 reported that the locals, clearly with a soft spot for the creature, plucked the branch from above the river with the spider attached.
It was then placed on an avocado tree in the town centre away from the flooded waters; but significantly closer to humans.
It's not the only critter spotted in the floodwaters. Video has also been uploaded of snakes in the river while a crocodile lunged at a car.
It comes as a group of Year 6 students who had been isolated by floodwaters were today being flown out in an evacuation timed to beat more wet weather expected, reported the Courier Mail.
More than 70 students and staff had been trapped at the Echo Creek adventure park near Tully since last Monday.
The first group of the staged rescue was flown out before noon.
The Bureau of Meteorology says the weekend's heavy rain is now easing, however there are signs a cyclone may be forming off the state's far north coast. This could have devastating effects on already damage-stricken regions.