In an interview, Scott Morrison said he had "not made any final decisions" on attending, suggesting it was a burden.
"It's another trip overseas... and I've spent a lot of time in quarantine," he told the West Australian newspaper.
The COP26 summit will be the biggest global climate crisis talks in years.
It is hoped that the 12-day meeting between world leaders in Glasgow, Scotland will produce the next emissions standards to slow global warming and keep temperature rise below 1.5C.
But Mr Morrison said he would consider other priorities, including the reopening of Australia's borders.
"I have to focus on things here and with Covid. Australia will be opening up around that time. There will be a lot of issues to manage and I have to manage those competing demands," he told the newspaper.
Australia - one of the world's top exporters of coal and gas - is one of 200 countries expected to present their updated 2030 emissions cuts at the meet.
Mr Morrison has said he wishes Australia to achieve net zero emissions "as soon as possible", but has not outlined any measures to do so.
His government has resisted committing to net zero by 2050 - a goal already pledged by the US, the UK and many other developed nations.
Australia has consistently been criticised for its slow climate progress and heavy reliance on coal-fired power - which makes it the most carbon polluting nation in the world per capita.