TR Group managing director Andrew Carpenter said the company wanted to do what they could to spread the message of mental health throughout the country.

The company teamed with Mike King's I Am Hope charity to create a rolling billboard to raise awareness around depression.

The group tied together with the symbol of the Mack bulldog and 'the black dog' term for depression, the idea of Mack the Hopeful Black Dog was born Carpenter said.

The truck was officially handed over to Winstone Aggregates at Hampton Downs last month and has been on the road for two weeks.

Dean East from Winstones said the response from the general public on the road and on social media had been overwhelming.

"It has been amazing, I took it down the motorway and there were toots and waves," East said.

"I took it into the first plant and when I came out there was a crowd around the truck taking photos - people love it."

Hopeful Black Dog has made a number of appearances over the past couple of months, including dropping by local high schools.

Brendan King of TR Group said the truck was also a reminder within the company to check on mates and workmates who might be struggling.

When Hopeful Black Dog was unveiled staff were told the truck was "an expression of love and support for all of you who have experienced, or are experiencing, mental health struggles."

"What we wanted to achieve with Mack was to give love and support to everyone affected by mental health issues and raise awareness in the community," King said.

"To let you know that you are not alone and that there is always support here and there is always Hope."

King said the messages on the truck were aimed at the friends and loved ones of those struggling.

"It is our job to ask our mates if they are okay and to offer them our time, our love, our support.

"It is our job as humans to look after each other. Love is not an emotion – love is an action – let the action be that you check on your mates and you ask them how they are – how they really are – and go with them to get help if it is needed."

Mack the Hopeful Black Dog can be seen on the roads and motorways of south Auckland.

It will be a special guest at the Bombay Truck Show in February 2020.