Education Minister Chris Hipkins told Newstalk ZB there had been "tremendous interest" from schools wanting to run the events.
"More than 85,000 students are expected to attend, with around 4000 employers joining them," he said.
"We're trying to get in early, and say look, there's a whole range of options out there."
The Government originally planned to fund 250 schools, but the Ministry of Education received almost 100 extra eligible proposals.
The overwhelming interest means every school that asked for funding, got it.
"It's about building better local links between education and employment", Hipkins said.
The events will be designed for young people to explore industry-specific careers, and allow employers to showcase trades careers to students and their families.
Auckland's Massey High School is one of those to benefit from the cash boost.
Principal Glen Denham said it was a great initiative.
"You can't tell me that there is one secondary school in this country that doesn't have at least a dozen kids that want to become a builder, an electrician, or plumber.
"I don't think you'd find any school that says 'no, we don't want that $3000 you can have it back'."
Denham hoped it would be a stepping stone to something more.
"I'm hoping that the feedback will be so great that other colleges say we need more money to do more of this."
This month, Newstalk ZB revealed 6100 New Zealand students have used fees free for trades training since the Government's flagship policy started in 2018.
New Zealand University Students Associate President Isabella Lenihan-Ikin said students were going into trades and vocational training as a direct result of the barrier-free alternative.
"It enables tertiary education as an option that isn't just for middle class or elitist people," she said.
Latest data shows more than 80,000 students have benefited from fees free up to August 2019.
