A group of downtown businesses won't get financial relief while their lawsuit against the City of Montreal and the STM over construction that's expected to last until at least 2020 moves through the courts.

The five restaurants — Kafein, Ferrari, Craft Grilled Cheese, Gourmet Burger and Mesa 14 — say business has plunged as much as 60 per cent since the transit authority dug up a large chunk of Bishop Street.

The city's transit authority, the STM, is building a mechanical ventilation station and the work is expected to last 42 months.

Jamie Benizri, a lawyer representing the restaurateurs, says his clients are on the verge of shutting down.

"It could be a matter of weeks, Benizri said. "There's already been lawyer notices coming in for non-payment of rent, we've had to slash employees, notices are coming in for unpaid taxes."

The businesses were hoping the Quebec Superior Court would force the city and transit authority to give them money upfront while they press their case.

They argued that without it they wouldn't be around by the time a judgement is rendered. Their plea was denied.

STM blames three-and-a-half year timeline on weak bedrock

Work started in October 2016 on the stretch between de Maisonneuve Boulevard and Sainte-Catherine Street. The STM is building a new ventilation station for the Metro.

Since then, the merchants have been face-to-face with a labyrinthine construction site that effectively fences off their storefronts.

The STM says the work on Bishop Street will take 42 months to complete. (Simon Nakonechny/CBC)

To compensate for lost revenue, the business owners are suing the city for a combined total of $33,000 per month.

The city's transit authority says the old ventilation station on de la Montagne Street needs replacing.

It says the three-and-a-half year timeline is because of issues caused by the area's weak bedrock.

But the merchant's group wants to know if it can't be done faster. They're also suing for $25,000 to hire an independent engineer to see if the project can be sped up.