There are some circumstances where it's acceptable to maintain a one-metre distance from others instead of two, Dr. Bonnie Henry said Thursday.

While staying two metres apart provides more protection, B.C.'s provincial health officer suggested less distance could suffice in certain "controlled environments," such as workplaces and classrooms.

"Two metres is the ideal, we know, for uncontrolled environments, particularly with people we don't know," Henry said during the province's latest modelling presentation. "But one metre is also good if you're with the same group of people you know and see regularly, such as work colleagues, classmates."

The updated guidance represents a significant shift from the messaging that health officials have hammered for months, beginning early in the pandemic, about how to keep safe.

It also comes amid concerns from teachers about whether classrooms will be spaced out enough when children return for the fall semester.

Henry stressed that one metre is not enough distance for face-to-face interactions, but pointed to rows of desks with children facing forward as one situation where less than two metres is necessary.

"It's a gradation. We know that two metres is better than one metre, is better than zero," she said.

"But if we're going to be in rows next to each other then somewhere in between there is perfectly safe."

Similar principles would apply in offices, provided people are in a small and consistent "pod" of people. Henry said workers should try to stay within their team, limiting visitors and interactions with people from other parts of the office.

"With the same people that you are with on an ongoing basis, one metre is probably fine for most of your interactions, recognizing that really important piece that we have to protect us all, which is staying home if we're ill ourselves," she added.