Labour Waiariki candidate Tamati Coffey said leaving whanau and iwi behind to pursue jobs in Auckland wouldn't be the "one or the other" scenario it currently was with a daily regional passenger and freight service.
"As the network expands to include areas such as Rotorua, this fantastic daily regional passenger and freight service will modernise our region, and provide growth which will overflow into our communities currently at risk of being left at the station.
"This plan will see greater job and lifestyle opportunities open up on both ends of the line."
Rotorua mayor Steve Chadwick said she did not wish to comment on the announcement.
Today's announcement was based on a rapid rail blueprint linking Auckland to Tauranga and Hamilton released last week by transport lobby group Greater Auckland.
"The golden triangle of Auckland, Hamilton and Tauranga contains half our population and economy," Ms Ardern said. "In the next 25 years, it is predicted to gain another 800,000 people - three-quarters of national population growth. It's time [our] growing region had a modern, rapid rail service.
"Labour will back the Regional Rapid Rail plan, starting with a $20-million commitment to establishing the passenger service. If stage one is a success and demand justifies it, Labour will look to invest in stages two and three of the plan - delivering passenger and freight services travelling 160km/h throughout the regions and south to Rotorua."
Labour has also said it would boost transport investment in regional projects by doubling the funding range in the Government Policy Statement.
National's transport spokesman, Simon Bridges, was scathing in his response to the announcement.
Mr Bridges said the Auckland-Hamilton-Tauranga rail line was the country's biggest freight route and did not have the capacity to also be a commuter line.
"Labour would kick economy-fuelling freight off this important line and replace it with empty carriages. The other, and possibly bigger problem, is that the journey by train between Auckland and Tauranga takes more than four-and-a-half hours by rail where a car or bus takes two-and-a-half hours and a plane 40 minutes."