City crews will be working overnight to repair a large sinkhole on downtown Ottawa's Elgin Street, accidentally caused by a construction crew.

The sinkhole opened up between Laurier Avenue and Lisgar Street following a water main break and flood around 2 a.m. Friday.

A company doing routine work for Enbridge accidentally cracked a 12-inch, 13-year-old water pipe, according to the city.

"It's not the city's fault. It was a private contractor doing work, not for the city but for another private entity," said Ottawa Mayor Jim Watson.

"They'll be responsible because they're the ones that have to make sure that they're digging and they're not cutting either hydro, or in this case a water main."

Elgin Street from Laurier Avenue to Gloucester Street is completely closed. City officials say the road will be closed until at least 8 a.m. Saturday.

The area stayed flooded until crews were able to plug the broken watermain, but the city said nearby businesses had only seen "intermittent" water loss.

"I understand there wasn't water initially, but then we got an e-mail that told us they'd found an alternate water supply in the building for the rest of the day," said a worker at nearby Place Bell Canada.

The nearby courthouse was experiencing some water issues, according to the city, with more than a foot of water spilling into a nearby parking garage.

CTV Ottawa's Norman Fetterley said the hole was about 20 feet deep and 20 feet wide around noon Friday.

With a report from CTV Ottawa's Norman Fetterley