TORONTO -- Ontario's top doctor was set to give an update Tuesday on COVID-19 as more local public health units imposed stricter health measures or issued new guidance in light of the fast-spreading Omicron variant.

Chief Medical Officer of Health Dr. Kieran Moore was due to hold a news conference at 3 p.m.

Peterborough was the latest region to instruct workplaces to have all non-essential staff to work from home if possible, as part of new measures set to take effect on Wednesday.

The new rules also require restaurants to ensure tables are at least two metres apart or separated by a barrier, and to set a cap on the number of patrons at each table.

Meanwhile, Ottawa Public Health warned of a backlog in its contact-tracing system due to a surge in Omicron cases. The health unit urged residents who test positive for COVID-19 to immediately self-isolate and alert their close contacts themselves.

The province's panel of expert advisers on COVID-19 estimated Monday that Omicron makes up 30 per cent of new daily infections, with cases doubling every three days.

Health officials in the Kingston, Waterloo and London areas have also announced new measures in response to the spike in Omicron cases, while Toronto has said it will delay the return to in-person work for city employees.

Ontario reported 1,429 new COVID-19 cases and virus deaths on Tuesday.

There were 162 people in intensive care due to COVID-19, including 98 people on ventilators.

Provincial data said 80 per cent of people aged five and older have two shots of a COVID-19 vaccine and 85 per cent have at least one dose.

There were 95 confirmed cases of the Omicron variant in Ontario on Tuesday. But public health officials have said they expect the number is much higher, and the strain -- believed to be highly transmissible -- will soon become dominant.