Prime Minister Justin Trudeau says "obviously overseas money coming in is playing a role" in Metro Vancouver's housing crisis.

But it remains unclear what his government will do to cool down the region's red hot real estate market.

"We know that there is an awful lot of capital that left Asia in the past few years," Trudeau told CBC Radio host Stephen Quinn on Friday morning in Vancouver.

"This reminds me of the challenges around the Hong Kong handover, where we saw in Yaletown all these new buildings come up after Expo 86, and then nobody was living in them because they were all bought as investments and insurance around the handover."

"We are all hoping to stabilize the market," he said. "We are on a trajectory that doesn't have any good outcome."

Which levers to pull?

But when pressed for specifics on what he could do, Trudeau said the federal government needs to move cautiously to avoid taking action that could negatively affect other regions.

"We need to make sure that any action we take is not going to make the situation worse. The law of unintended consequences is very, very present in housing markets," he said.

"As a federal government, levers we use here in Vancouver and perhaps Toronto could have extremely negative impacts on housing markets in Calgary or Montreal or Halifax," he said.

"We need to make sure that we are reining things back a little bit in a way that doesn't completely devalue those people whose equity is still in their homes. "

"Getting that balance right is going to be really important," he said.

That's why Trudeau planned to sit down with Metro Vancouver politicians, activists and housing experts later Friday morning for a roundtable discussion on possible solutions.

"This is a very localized problem in many senses to the Lower Mainland. How do we make sure we are helping here in exactly the right way?"

Transit construction to start next year

Trudeau arrived in Metro Vancouver on Thursday to sign a $900-million transit funding agreement with B.C. — the first such program in Canada.

The funding announcement included cash to upgrade existing infrastructure and equipment and start designing and planning the construction of two new rapid transit lines.

But it did not include a long-term commitment to fund the actual construction of two transit lines in Surrey and Vancouver.

Nevertheless, Trudeau said the aim is still to start construction on the two projects "as soon as next year."

"There are a lot of partners to line-up. People expect us to build these as quickly as possible," he said, adding the projects also need to be handled responsibly.

The government decided to split the funding into two phases to jump start the projects as quickly as possible, he said.

And he promised the funding commitment for the construction stage would be coming soon.

"Phase two is all about the big builds, the new great important projects that are going to make a real difference, which take a little more time."

Supervised injections supported

Trudeau was also asked if his government would support the B.C. government's plan's to open five new supervised drug injection sites in the Vancouver area in the coming months.

The previous Conservative government put laws in place that required special permits for the supervised sites to operate with medical staff.

Trudeau said his government would move to help open the sites as soon as possible, while working to repeal the legislation.

"Repealing legislation takes longer than I would like to take. We are going to try and work around it as quickly as we can while still respecting the law," said Trudeau.

"We believe that supervised injection sites save lives and we have instructed the health minister ... to ensure that legislation does not impede their capacity to move forward."