Twenty-three people were taken to hospital with minor injuries after a series of crashes on icy roads in the Greater Toronto Area on Tuesday evening.

There were more than 70 collisions in the GTA in 2½ hours Tuesday, Sgt. Kerry Schmidt, spokesman for the Ontario Provincial Police highway safety division, said.

Officials blamed freezing rain for the poor driving conditions.

Between 8 p.m. and 9 p.m. Tuesday, about eight people were taken to hospital after four separate crashes along Highway 427, said Stewart Morris, deputy commander for Toronto Paramedic Services.

The crashes occurred on Highway 427 in the area of Eglinton Avenue West, Highway 401, Rexdale Boulevard and Dixon Road, he said.

Six people were taken to hospital by the Toronto paramedics emergency support unit bus, while two people were transported by ambulance. All suffered minor injuries.

One of the crashes involved nine cars and two trucks on Highway 427 at Eglinton Avenue West.

Two cars collided head-on in a multi-vehicle crash in Toronto Tuesday evening on Highway 427. (CBC)

At 9:10 p.m., an accident on the Highway 410 off ramp at Derry Road in Mississauga sent 15 people to hospital with minor injuries.

Up to 40 vehicles were believed to involved in that crash.

"Most of them just slid into each other," Jeff Walsh, superintendent for Peel Regional Paramedics, said Tuesday night.

Environment Canada said the conditions were caused by what it called "patchy" freezing drizzle and light snow. It issued a winter weather travel advisory at the time that warned of hazardous driving conditions.

Approximately 30 vehicles including tow trucks in collision on the offramp from Hwy 410 southbound to Derry Rd. Minor injuries. <a href="https://twitter.com/hashtag/onstorm?src=hash">#onstorm</a> <a href="https://t.co/h9QWlaSrGK">pic.twitter.com/h9QWlaSrGK</a> —@Media371

OPP's Schmidt said Highways 401, 403, 427 and 410 were the hardest hit with collisions. No serious injuries were reported, but there were several rollovers.

"Just slow down," he said. "Don't be in a hurry. It might take you a little longer, but it'll save you from getting into a crash."

The situation was no better in Peel Region, where police said there were multiple crashes on Highway 410.

Toronto Paramedics received multiple calls about collisions on Ontario highways, including one involving nine cars and two trucks on Highway 427 at Eglinton Avenue East. (CBC)

A Ministry of Transportation review indicated the temperature dropped quickly from 1 C to -2 C between 7:30 p.m. and 8:30 p.m. At the same time there was isolated flash freezing rain in the GTA.

"Our initial review indicates that the area maintenance contractor responded quickly and appropriately to the conditions and that roughly 50 trucks were deployed to spread salt throughout the western GTA last night," said Ministry of Transportation spokesperson Kwok Wong in an email statement.

Toronto's Pearson International Airport advised travellers on Wednesday morning to check their flight status before heading out.