TORONTO -- Ontario’s Chief Medical Officer of Health has laid out what his team needs to see before starting to lift restrictions imposed as a result of COVID-19.

Speaking at a news conference on Thursday, Dr. David Williams said that stopping community transmission is the key to keeping the virus at bay.

“Our public health measures said we would like to see a steady decline over a two week period,” Williams said. “So we’re seeing a decline over the last five or six days, so we want to see that go well below 200.”

Referring to the daily number of confirmed cases by way of community transmission, Williams said that the last time Ontario reported fewer than 200 cases of COVID-19 caused by community transmission in a single day was in early March.

“We would like to be well below, well below 200 to get us back to where we were in the early part of March. Once we start to get to around 150, 160 we started to see more and more community spread cases.”

READ MORE: 'Get ready': Ontario premier unveils rules for businesses ahead of reopening

Williams said that threshold represents a crucial tipping point between when transmission of the virus can be effectively monitored and when it becomes impossible to track.

“We have to get back to somewhere around there, so that we can be assured that all our cases have been followed up and we can identify what was the source, where did they get it, what was the contact and other ones in that line.”

“That sort of containment is very critical to relaxing the public health measures and to inform the public of the relative safety of social activity in that regard.”

Williams told reporters that as of Thursday, Ontario’s daily number of community spread cases is somewhere in the low 200s, which he said is encouraging. In recent days, Williams has said that overall, the daily count of new cases shows a “50-50”split between new cases in long-term care homes and virus spread in the community.

The actual data on community transmission in Ontario is not entirely clear, something Williams is asking Ontario’s 34 public health units to help address.

On Wednesday, Williams said he is hoping those teams will be able to collect more detailed information about how the virus is spreading in new cases and the possible sources of transmission.

Earlier this week the Ontario Premier Doug Ford unveiled the government's three-phase plan to reopen the province following weeks of shutdown.