Considered as essential services during the coronavirus pandemic, public transport continues to operate. But many vehicles and carriages are bereft of passengers amid restrictions on travel and work-from-home guidelines.

Traditional peak-hour queues have become a trickle, with masked drivers often setting off with only one or two seats filled.

Public transport providers are carrying out extra sanitising of buses, trams and carriages for those who do travel, and taking other measures to protect drivers.

Cash payments are no longer accepted in many areas - meaning some Tasmanians are having free rides.

Transport for NSW buses have seating immediately behind drivers cordoned off and the front Opal-card readers covered so passengers don't linger near the driver.

But some passenger behaviour has not improved.

A 2019 survey by the NSW Transport Workers Union found 81 per cent of drivers endure daily verbal abuse.

Union state secretary Richard Olsen says drivers are "still copping dangerous behaviour from passengers".

He told AAP a passenger spat at a driver on Wednesday, and another passenger sneezed on a driver's arm last Saturday.

COVID-19 test results are awaited for both drivers.

Patronage across all Transport for NSW services is down by 75-85 per cent in the past four weeks, a spokesperson told AAP.

But the agency has no plans to reduce services.

"By maintaining the existing level of service on the NSW public transport network, customers are able to better practise social distancing when using the network for essential travel," the spokesperson said.

In Victoria, Daniel Bowen from the Public Transport Users Association estimates patronage across the state's trains, trams and bus services is down about 90 per cent.

"I wouldn't be surprised if it is higher than that," he told AAP.

"Under normal circumstances, peak hour is pretty packed on most services and at the moment it's near empty."

Mr Bowen anticipates services will be cut as the state government tightens measures designed to stop the spread of the coronavirus, but said the public transport network must continue operating for essential workers.

"The key will be making sure it's still useable for those who need it," he said.

Victoria's head of transport services, Jeroen Weimaric, said changes to services may be needed.

"This will only be done following expert medical advice and we'll communicate with passengers ahead of time should that be needed," he told AAP.

Perth's public transport services will be significantly reduced from Monday for three weeks, after a reported patronage reduction of about 80 per cent.

And passengers who assault or threaten harm to bus drivers in Western Australia are now subject to harsh new penalties, including 10 years' jail for assault.

While Queensland's long-haul train and bus services have been reduced or suspended to slow the spread of coronavirus, TransLink says public transport continues to run as scheduled throughout the state's southeast.

"Present health advice is to limit all non-essential travel and we thank our customers for following this advice," a spokesperson said.

"As a result, we have seen passenger numbers drop by about 70 per cent on some services over the past fortnight."

Tasmania is the middle of a two-week bus fare amnesty to give passengers time to access a smartcard or other cashless payment options, after all state bus services went cashless last Friday.

"Free travel for the next two weeks is not an invitation to undertake additional travel, passengers should restrict themselves to essential journeys," the Department of State Growth said when announcing the change.

Australian Associated Press