London has tightened its congestion charge for cars driving through the city centre.

Diesel and petrol vehicles over 11 years old will have to pay an extra 10 pounds (AU$16) each day, on top of the existing congestion fee introduced 14 years ago.

It is estimated that about 34,000 drivers will now pay more than 20 pounds (AU$36) per day just to enter the city's central areas.

London mayor Sadiq Khan said the health benefits of the so-called “T-charge” would far outweigh the costs.

“We've got a health crisis in London. We've got a situation where the air in London is a killer and makes people sick,” Mr Khan said.

“The economic cost of the poor quality air each year in London alone is 3.7 billion pounds. That's why you've got the toughest vehicle emissions standard anywhere in the world.”

Critics argue the new fee will disproportionately affect poorer Londoners, who are already contending with rising costs of living and are more likely to drive older cars.

Britain's Road Haulage Association says it will drastically affect businesses.

But Mr Khan said the T-charge is designed to change driver and business behaviours.

“Those who drive the most polluting vehicles change their behaviour and move to cleaner vehicles, or move to public transport, or walk in and cycling when they can,” he said.

The T-charge is due to be replaced by an even stricter Ultra-Low Emission Zone in coming years, which will see even higher fees.

Professor Stephen Greaves, from the Institute of Transport and Logistics Studies at the University of Sydney, says similar charges are almost certainly on the way for Australia.

“Yes, I think that [Australian cities should follow London's lead]. Some of our older trucks are 20 to 25 years old. Some don't even have particular filters on them,” Professor Greaves said.

“Fine particles and other cancer-causing toxins are more prevalent in diesel, and there's been an awful lot of evidence both here in Australia and overseas to corroborate that.

“Going through residential areas often making deliveries, so they're sitting there idling. I think we should be focusing on that local pollution issue.”