Support for One Nation fell by three percentage points to 26 per cent in July, while the coalition bounced back from 20 per cent to 23 per cent in a Resolve Political Monitor survey released on Sunday night.
Labor's backing was steady at 28 per cent.
Along with a separate DemosAU poll, which also showed a mild dip in support for the right-wing populist party, the results reinforced a decline in support for Senator Hanson since her controversial appearance at the National Press Club.
She used her first speech at the forum to call for Australia to be a "monoculture", while also taking aim at other policies such as paid parental leave.
Labor frontbencher Mark Butler said One Nation might feel like a useful outlet for people frustrated by developments such as high living costs.
"But when you actually sit back and think about the so-called solutions they have for the country, I think more people are realising that would actually make things worse, not better," he told Nine's Today program on Monday.
Opposition energy spokesman Dan Tehan put the recovery in coalition support down to its hard work on tax, immigration and energy policies.
"It's all very well to come up with simple policy solutions which sound good but have no foundation to them," he told Sky News.
"What you've got to do is actually do the hard yards."
Liberal leader Angus Taylor has taken a more confrontational approach to the rival right-wing party in recent weeks, taking aim at its economic credentials.
But Mr Butler said the opposition leader was yet to work out how to manage One Nation.
"Do they live with them, do they live without them?" he said.
"Does he want to mimic them or does he want to contest them?"
In the Resolve poll, which surveyed 2252 people between July 6 and 11 for Nine newspapers, support for Senator Hanson as preferred prime minister dropped by eight points to 25 per cent.
Prime Minister Anthony Albanese made a comeback with 33 per cent of people preferring him for the role, up from 29 per cent in June.
Mr Taylor sat on 21 per cent, two points higher than previously.
One Nation MP Barnaby Joyce said the fluctuation in the polls was an indication of Senator Hanson's direct style on issues such as multiculturalism.
"She doesn't try to gild the lily, she's straight down the barrel with what she says," he told Seven's Sunrise program.
Maintaining social cohesion and preventing a repeat of the Bondi terror attacks required bravery, Mr Joyce added.
That included acknowledging some people didn't belong in Australia, he said.
"If you believe that other people's rights are diminished next to yours, that you have a license to kill them, that is part of your religion, that you want to take it to the literal extent that people who are gay can be thrown off buildings ... you don't belong here."
A DemosAU poll published by Capital Brief showed Senator Hanson's net favourability dropped six percentage points to negative nine per cent, still well ahead of Mr Albanese on negative 23 per cent.
While 61 per cent of Australians believed that immigration should be substantially reduced, a clear majority of voters rejected her suggestion that Australia should be a monocultural country.
On a primary vote basis, One Nation still led Labor 29-26 in the DemosAU poll.
The surveys come two weeks after Newspoll and Redbridge polls also showed Senator Hanson's popularity had taken a tumble since her press club appearance.
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