"With growth comes significant increase in traffic movement and freight movement. You see that every time you travel State Highway 29 over the Kaimais.
"The sheer level of trucks on that road signals it's already heavily loaded."
With a tunnel, it would be possible to get between Tauranga and Hamilton in 45 minutes.
"The numbers to do it will be huge but there's a sense of inevitability about it. The people of Tauranga will demand it so instead of doing it last minute, let's start," he said.
"I look at somebody like Sir Dove-Meyer Robinson. He looked at what Auckland could be " one million people by the turn of the century " and people scoffed at him."
Mr Muller said the situation in the Western Bay was the same now and believed the tunnel was needed rather than tweaking the "difficult road up and over the Kaimais".
"Let's be bold and bring it forward to our lifetimes so our kids can reap the benefits of it as opposed to looking back in 2050 and saying, 'if only we had done it sooner'."
It would be an extremely expensive capital project, which would require a significant amount of funding from the Government, he said. Tauranga Mayor Stuart Crosby also supported the idea.
"There's absolutely no doubt that State Highway 29 will require some investment and hopefully four-laning from Cambridge through to Tauranga to compliment the rail network. If a tunnel stacks up economically, that's certainly the way to go," he said.
"It does make sense. The good news is we have a very strong working relationship with the councils and the crown."
NZ Transport Agency Waikato highways manager Kaye Clark said the agency was working with the Bay of Plenty and Waikato regional transport committees, looking at the road safety, freight efficiency, and route resilience of the corridor between the Port of Tauranga and the Waikato.
"This work includes looking at both rail and State Highway to identify any issues and the need for solutions," she said.
"We have looked at the possibility of a tunnel through the Kaimai Range in the past. We have not discounted it in the long-term future, however, our cost-benefit analysis indicated that the cost of building a tunnel would significantly outweigh the benefits of the project at this point in time."