Labor has blasted Michaelia Cash for refusing to say how much taxpayers are paying The Block star Scott Cam to promote vocational education in his new role as “national careers ambassador”.

At a press conference on Thursday the skills and employment minister said Cam’s pay for the 15-month role was “commercial in confidence” but suggested spending was “about outcomes” and reflected the fact the government had secured “one of the highest profile people in Australia”.

Labor and the unions suggested the Coalition should stop hiring “celebrities” and properly fund Tafe and apprentices instead, claiming $3bn has been cut from vocational education since it came to office.

Cash said the government is “determined to shine a light on how fantastic vocational education and training is” and described Cam’s role as “to work with us to really get that message out”, explaining she would be “out and about with Scott attending high-profile events” to do so.

Cash described Cam as a “former apprentice around 40 years ago now” and “literally a household name in Australia”, citing the fact he ran his own business and had employed apprentices as qualifications for the role.

Cam did a three-year carpentry apprenticeship at age 17 and has worked as a television presenter since 2000 when he first appeared on Backyard Blitz. He won a gold Logie award in 2014 for hosting renovation reality television show The Block.

Cam told reporters he was “very privileged” to have the role, adding he is “not taking it lightly”.

Cam said the National Careers Institute provides a “one-stop shop” for people to get information about vocational education and careers pathways and “my role is to get the information out there, to let them know that it’s there”.

Contracts on AusTender show in 2009 the Labor government paid $74,250

to SWC Contractors for “representational services by Mr Scott Cam at Centrelink Job Expos”.

A separate contract published in 2011 suggests the same company was paid $76,500 for “sponsorship of event or celebrity” for a “representative for job expo”.

In February 2013 Treasury officials told Senate estimates the Australian Taxation Office paid $77,962 to Media Heads to create a series of YouTube videos called ‘Build a better business – lodge online’ featuring Cam, although it did not say what part of the fee was paid to Cam.

“Mr Cam was used because he is a well-recognised celebrity with broad demographic appeal and credibility with small business,” Treasury said in an answer to a question on notice.

In November 2016 Cam featured in an education department advertisement with Karen Andrews, then the assistant minister for vocational education and skills. The video has 866 views despite almost three years online.

On Thursday Labor’s shadow education minister, Tanya Plibersek, responded that Scott Cam is “a good bloke, but if the Liberals were serious about fixing the skills crisis they’ve created, they’d stop hiring celebrities [and] start funding TAFE and apprentices”.

At a doorstop in Melbourne, Plibersek said it was unacceptable for the government to refuse to say how much Cam was paid.

“If the government believes that this is a worthwhile investment they should be upfront about what they’re spending,” she said. “But this isn’t about Scott Cam.”

In the 2019 budget the Coalition promised to create 80,000 apprenticeships through employer incentives, unveiling a $525m skills package with just $55m of new money, with the vast majority ($463m) the result of reallocating unspent funds in the Skilling Australians Fund.

Plibersek said there were 150,000 fewer apprentices and trainees in Australia today than when the Liberals came to office in 2013.

“We have more people dropping out of apprenticeships today than completing them,” she said.

“We’ve got fewer apprentices and trainees today than 10 years ago and all that while we’ve got 1.9 million Australians looking for work or looking for more hours of work and we’ve got three quarters of Australian businesses saying they can’t find the trained and skilled staff they need.”

Producers of the ABC TV political satire Utopia later tweeted about an episode that talked about appointing Cam as an ambassador.