Réal Ménard, the executive committee member responsible for transportation, said the city needs $240 million a year to meet its objectives, but it's getting by on a third of that — some $80 million.
He said finding new sources of financing for public transportation is going to be a key issue for whoever wins November's municipal election.
"I think it is going to be a major debate, a major issue for the next campaign," Ménard said.
"All options are to be considered," he noted, listing tolls, a gasoline surtax and the creation of a municipal transportation fund.
Since the plan's adoption in 2008, there has been a 26 per cent increase in ridership on the bus and metro system.
The city has also added almost 200 kilometres to its network of bicycle paths.
However, other projects, such as extending the blue line on the metro, adding an express bus to service on Pie IX Avenue and building a tram line all remain unrealized.
Marvin Rotrand, an independent councillor and vice-president of Montreal's transit authority, the STM, said the provincial and federal governments must step up with more financing.
However, he said the goals of the ten-year plan were perhaps overly ambitious from the start.
"In many ways, this plan was more of a vision than a step-by-step concrete plan," he said.
Rotrand said the plan's adoption has led to a vigorous debate about public transit and biking, and he says that alone is progress.