Past and present WorkCo board members, directors, employees, trainees and apprentices were among the 100-strong crowd at the opening.

The company's first employee and now WorkCo Limited chief executive John Ackland and WorkCo's first apprentice Brendan Kaczynski unveiled a commemorative plaque.

WorkCo general manager Dean Luciani said it was a pleasure to open the Dimboola Road office building.

Mr Luciani thanked Wimmera contractors and sub-contractors, apprentices and Horsham Rural City Council surveyors for their work on the building.

"Twenty-five per cent of our contracting was done by young people and that's something we're immensely proud of," he said.

"We're very committed to this region because it's where we started.

"Led by principle contractor Locks Constructions we have seen many people put their skills on display.

"Our local tradespeople are so skilled, professional and easy to get along with."

WorkCo chairman Donald Carter said the opening was an exciting day for the company.

"WorkCo has a fairly big footprint across Victoria and this new building is a tremendous asset for the community," Mr Carter said.

Mr Ackland said the new office was a 'magnificent complex'.

Mr Kaczynski said WorkCo had been a big part of his life.

"Back in 1986 I was only 16, was still at school and going for a job as an apprentice chef at Ararat," he said.

"To have someone outside the workplace as a mentor and have someone to talk to was a great help.

"I certainly didn't think 24 years ago I'd be standing here doing this. They gave me a start in my working life and I certainly can't thank them enough."

The Mail-Times will publish a special feature on the building opening on Wednesday.