Celebrity tradesman and TV presenter Scott Cam has defended his taxpayer-funded pay cheque from the federal government for his work as national careers ambassador.

In October last year the employment and skills minister, Michaelia Cash, announced Cam’s appointment to the role promoting vocational education, but refused to reveal his pay, arguing it was “commercial in confidence”. It was later revealed Cam would be paid $345,000 for 15 months’ work.

The star of The Block has so far pocketed $145,000 to steer students away from universities and instead think about a trade.

Skills Department officials told Senate estimates last week that Cam had appeared in three short videos, made four social media posts and put a profile on a government website.

Cam launched his national tour alongside Cash on Tuesday, saying he has 12 appearances booked so far.

The gold Logie winner was questioned extensively on Sky News on Tuesday about his salary and work in the role so far. Cam insisted he has done “many, many” interviews in the role, saying it had not properly kicked into gear yet as students have been on school holidays.

“If you did your homework and knew what you were talking about, you’d work out that all of the tours and appointments we’re going to see are school-based,” he said. “Over the summer all of those facilities are closed, there’s no students there. I think that would be a waste of taxpayers’ money if I was standing at an empty school.”

Asked if he thought it was a fair salary, Cam said: “Of course I do. That is the value of the brand and the profile the government deem fit to pay me. I have a high profile and the government wanted to utilise that.”

Pressed further about whether his salary was the government’s initial offer, Cam said: “My management and the government discussed the fee, that’s none of your business … How that came about is between my management, myself and the government.”

He later backtracked, conceding taxpayers had an interest in the figure but not in how the role came to be.

“I think ‘defensive’ is a fair word to use,” the deputy opposition leader, Richard Marles, told Sky in relation to Cam’s interview. “Ultimately, what the government needs to be doing in relation to VET is to properly fund it.”

The previous Labor government also paid Cam to open trade fairs.