The Act leader said polls showed for the first time since the Global Financial Crisis, most New Zealanders said the country was going in the wrong direction.
He attacked the Government's responses to the Delta and Omicron outbreaks.
"The Government needed an actual outbreak before it acted on Delta. That cracked the illusion. Finding ourselves in the exact same situation with Omicron four months later shattered it."
And he said the economy was suffering.
"Most people need to work for a living. The streets are empty because they can't risk their household being isolated for 24 days thanks to draconian isolation requirements."
He added: "The Government's failure at everything but locking out, locking down and borrowing printed money is now felt by every person every day."
Horizons seemed to be receding for regular people who wanted to achieve even modest financial success, he said.
"They work longer and harder than ever but they never seem to get ahead, unless they surf the property wave. Why does a comfortable life seem so difficult to achieve?"
'Zombie bureaucrats'
Seymour said spending on a bloated public service was one reason for that, although he excluded nurses, doctors, police and teachers from his list of superfluous or overpaid public sector employees.
He lashed "zombie bureaucrats" and redundant government departments.
Seymour asked the audience if anyone had recently visited Video Ezy, shopped at Deka, or bought a copy of the Auckland Star.
"We need to stop assuming government departments and activities should continue because they always have."
He said inflation was another major concern.
"It is partly the result of supply constraints and inflationary pressures that affect the whole world, but we have it worse because of our own policies.
"We had the second largest government stimulus behind the US who have the worst inflation, even before our spring lockdown."
Seymour said the Government had failed to boost intensive care unit capacity, which would have helped the pandemic response.
"A million Kiwis offshore know anyone can quarantine an island. It took a hundred million years of continental drift, but the work was already done for Jacinda."
Seymour alluded to recent controversy involving pregnant journalist Charlotte Bellis, who was stranded in Afghanistan.
"We have entered Wonderland where the Red Queen is talking backwards, and that great feminist organisation called the Taliban gave a New Zealand woman asylum from the policies of her own Government."
Seymour's speech was delivered shortly after Ardern and the Government revealed a five-step international border reopening.
The first people allowed to arrive from abroad will be vaccinated New Zealanders from Australia on February 28.
The border will reopen to Kiwis in the rest of the world from Monday, March 14.
"Closing the border is easy. The hard part is safely reconnecting with the world," Seymour said.
He said the popularity gap between the centre-left and opposition parties was closing.
"One hundred thousand more voters changing their mind about Jacinda is now enough to change the Government."
2023 Election issues
National Party leader Christopher Luxon recently said the Government performed badly last year. He admitted Labour performed well during the pandemic in 2020.
Asked where he thought the Government had performed well, Seymour told the Herald: "Initially, we used our strategic advantage as an island nation to block off and buy ourselves time."
Yet he quickly added: "As soon as we did that, the question was 'how do we ensure our isolation does not become our greatest weakness?' "
Seymour said New Zealand had not safely reconnected with the world early enough.
"Now, having failed to do that, we've got Covid and we're in the No Man's Land where we have half a border, Omicron's in the country, the economy can't keep going."
He said major 2023 election issues, as long as the pandemic had subsided, would include national identity, crime, welfare dependency and education.
"We need to be a multiethnic, outward-looking nation state where no two children are born with different sets of political rights."
And he said Labour was stifling aspiration with over-regulation.
He said Labour was beating down landlords, farmers and small business owners.
"We need a change in our culture towards celebrating success."
