The bushfire smoke blanketing Melbourne and much of Victoria is expected to persist for at least the first half of the week, and air pollution in the city is forecast to worsen to “very poor” and “hazardous” levels.

The smoke is also affecting air quality in Gippsland, North East, Alpine and Geelong regions, and is expected to fall to “hazardous” levels in the Latrobe Valley.

People may experience coughing and irritation of the nose, throat and eyes over the next two days from smoke. Photo: ABC News/Gemma Hall

The air quality in some Melbourne suburbs, including Dandenong and Brighton, has already been measured at “very poor” by the Environment Protection Authority (EPA).

Though some of the smoke has come from fires in Victoria’s north-east and East Gippsland, most of it has actually drifted across from Tasmania, EPA chief environmental scientist Andrea Hinwood said.

“We’re not expecting this to change until Wednesday,” Dr Hinwood said.

“We might see some light relief tomorrow but we might not.”

Dr Hinwood said rain had unfortunately “done almost nothing”.

“Drenching rain would be terrific because it would knock it out. But the current amount is insufficient and there’s too much smoke.”

The EPA is advising people stay indoors and close up their homes to keep air quality inside at its highest. Photo: ABC News/Cathy Jacobs

The smoke has even prompted tennis great Novak Djokovic to suggest Australian Open organisers consider delaying this year’s event if the problem persists.

‘A threat to life for some’

Victoria’s chief health officer Brett Sutton said people may experience symptoms such as coughing and irritation of the nose, throat and eyes.

Vulnerable people — such as those aged under 14 or over 65, those with diabetes or heart/lung diseases and pregnant women, children 14 and under, and people over 65 years old — have been urged to minimise smoke exposure by staying indoors.

If they need to be outside, they should wear P2 or N25 masks, Dr Sutton said.

“We know it’s a threat to life for some people.”

Dr Sutton said asthmatics should put their asthma management plan into action, and those who did not have a plan should see a doctor to get one.

He said symptoms could also appear in people with undiagnosed asthma.

“People with ongoing cough, wheezing, tightness of the chest, may have asthma and should see a GP,” he said.

He said smelling smoke inside was a sign of poor insulation in Australian homes and an indication of the high smoke levels in the city.

Dr Hinwood advised people to “close everything up” in their homes and seal their doors.

“Now is a good time to do that because this will persist for the next few days,” she said.

“Some homes are terribly leaky and will be problematic. Go to the library or shopping centre to take a break in these conditions.”

Melbourne’s air quality is not forecast to improve until Wednesday. Photo: ABC News/Gemma Hall

Dr Sutton said face masks were “not a cure-all”.

He said P2/N95 masks can act as additional protection for vulnerable people forced to be outside.

“But masks can give you a false sense of security,” he said.

“It doesn’t mean it’s okay to go outside. They have to be fitted properly and when they are fitted it can make it difficult to breathe.

“Surgical masks, bandanas are not going to do the job.”

-ABC