"The damage on Morrison's personal ratings amounts to an eight-point drop on approval to 37 percent and an eleven point rise on disapproval to 59 percent," wrote poll commentator William Bowe.
Morrison began the crisis insisting local authorities had enough resources to handle the fires and exhausted volunteers firefighters "want to be there".
He also repeatedly stated that Australia was doing more than enough to meet its emission reduction targets, prompting a series of large-scale street protests.
Seeing a backlash, Morrison has since deployed the military, launched the largest peacetime call up of reserves, pledged billions of dollars in aid, increased payments to firefighters, and suggested more work may need to be done on emissions.
The fires have killed at least 27 people, burned an area the size of South Korea, and shrouded Sydney in toxic smoke for weeks on end.
Morrison on Sunday acknowledged a groundswell of anger about the climate-fuelled fires.
The prime minister -- a staunch supporter of fossil fuel industries -- said emissions targets would "evolve" but ruled out curbing Australia's vast exports of coal.
"In the years ahead, we are going to continue to evolve our policy in this area to reduce emissions even further and we are going to do it without a carbon tax, without putting up electricity prices and without shutting down traditional industries," he told public broadcaster ABC.
The polls also showed Morrison's conservative coalition had lost the lead over the opposition Labor party, which now leads the preferred vote 51-49.
The next general election is expected in or before 2022.