Police are telling motorists to exercise caution when driving in Toronto's downtown core now that workers have completed the final stages of the G20 security fence.

A construction worker puts the finishing touches on part of the security fence outside the Toronto Metro Convention Centre for the G20 summit. (Nathan Denette/Canadian Press)

Motorists out on the roads at the start of Monday morning rush hour discovered a number of road closures that began Sunday evening.

The closures affected intersections in an area bounded by King Street to the north, Lakeshore Boulevard to the south, Yonge Street to the east and Spadina Avenue to the west. Those roads reopened around 6 a.m. Monday as work on the fence wrapped up.

The three-metre-high concrete and metal fence stretches for 3.5 kilometres.

An increase in the number of uniformed police officers could be seen in the area over the weekend, especially close to the summit site at the Metro Toronto Convention Centre, where leaders will be meeting June 26-27.

Police stopped some pedestrians Monday at the corner of Simcoe and Wellington streets and asked to see identification. The area is located in the innermost security zone, also known as the red zone, which includes the convention centre and nearby buildings.

According to police, the requests for identification were carried out prematurely. Toronto police say a few eager officers didn't read the directive telling them they weren't expected to start verifying IDs until Thursday.