The northern corridor has 573,000 residents, which is 29 per cent of Perth's population.
A video presentation, titled WA's Growth Coast, was shown before mayors Tracey Roberts, Troy Pickard and Giovanni Italiano spoke about the strengths and opportunities in the region along with the challenges over the next two decades.
Mr Pickard said the region was one of Australia's fastest growing areas and opportunities existed in innovation, tourism, international investment and the digital future.
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READ NOW"There are great benefits in tackling these issues from a regional perspective and working together to promote economic development and job creation for residents," he said.
Mrs Roberts said the region needed to generate a minimum average of 4500 new jobs each year to achieve 60 per cent employment self-sufficiency by 2031.
"Appropriate access to industrial areas and activity centres is of critical importance as is the timing of key economic infrastructure," she said.
Cr Italiano said with the downturn in the mining sector, WA needed to diversify its economy and look to other sectors such as tourism to provide future investment and jobs.
"According to State growth targets, tourism expenditure is expected to double between 2010 and 2020," he said.
"With the overall achieved growth rate of 22.2 per cent (from 2009-2013), the region needs support from the State and Federal Governments via funding for new infrastructure into tourism and public facilities to achieve these targets."
In August, a Tri Cities Alliance delegation will meet key Federal ministers and stakeholders to discuss funding opportunities for the region.