David Jones says carbon tax fears among well-heeled shoppers have contributed to a record fall in sales which has forced it to slash its second half profit guidance.
As Ms Gillard delivered a passionate speech defending her controversial policy, David Jones boss Paul Zahra declared he had "no doubt" the carbon tax debate was a factor in slowing sales.
"As far back as our records show, we haven't seen these sorts of declines in sales," he told reporters.
Mr Zahra's comments came a day after the Westpac-Melbourne Institute index of consumer sentiment in July fell to its lowest level since the height of the global financial crisis.
At the National Press Club in Canberra, Ms Gillard confronted criticism of the way she is communicating her clean energy future message to the community.
"It doesn't come easy to me to expose my feelings as I make these decisions," she said, describing herself as the shy girl who studied and worked hard.
"I've brought a sense of personal reserve to this, the most public of professions.
"And the rigours of politics have reinforced my innate style of holding a fair bit back in order to hang pretty tough.
"If that means people's image of me is one of steely determination, I understand why."
Asked how the media should cover the climate change debate, Ms Gillard was blunt: "Don't write crap. Can't be that hard."
Opposition Leader Tony Abbott on Thursday took his anti-carbon tax campaign to the town of Gatton, west of Brisbane, and later to a carbon tax forum in Brisbane's CBD.
In Brisbane Mr Abbott faced 112 uncommitted voters, yet he appeared relaxed as he walked into the meeting and greeted many of them individually.
While most of the questions allowed the opposition leader to push his standard lines against the carbon tax he was at great pains to make it clear he was not there to push the idea of doing nothing as an alternative to the tax.
"I think that climate change is real," he told the Brisbane audience.
"This is not a debate about climate change, this is a debate over how to deal with it.
"The argument is `Do you want a new tax or do you want direct action?' That's the discussion."
But he said he was not prepared to sacrifice the economy for the environment, saying countries with the strongest economies were best able to provide for their environment.
"I don't think we can really respect the environment and protect the environment by trashing our economy.
"Australia has, relatively speaking, a terrific environment because we can afford to look after it," he said.
"The economy does not always come before the environment, but the environment should not always come before the economy either, it's got to be a question of balance."
He also attacked the tax for being "anti-aspirational" and for the negative impact it would have on the value of the Australia dollar, saying it would depress it.
The most welcome comment of the night came when Mr Abbott said in response to a question that his direct action policy would not push up the price of Tim Tams.
Ultimately he said the future of the tax would be decided by a vote and he would accept the outcome.
"Now I'm confident that I can carry that vote because I think the arguments are on my side," he said.
Earlier in Gatton, Mr Abbott had rejected Treasurer Wayne Swan's claim his carbon tax "scare campaign" was partly to blame for the drop in consumer confidence.
"What's contributing to poor confidence is the treasurer's carbon tax and if he wanted to restore confidence he could do it at a stroke," Mr Abbott said.
Mr Swan was in New Zealand on Thursday to discuss plans with Kiwi counterpart Bill English to link the two countries' climate-pricing schemes.
Mr Swan said Australians could be comforted that NZ's scheme - introduced last July - was working effectively.
"The sky didn't fall in when the scheme was introduced in New Zealand and the sky will not fall in when the scheme is introduced in Australia," he told reporters.
Mr Swan's opposition counterpart Joe Hockey defended the coalition's alternative "direct action plan" after criticism from economists.
The Economic Society of Australia this week found 59 per cent of economists believe the government's carbon plan is a good one but just 11 per cent support the coalition plan.
"I have a great deal of respect for economists but at the end of the day they are not elected to run the country," Mr Hockey said.
