ANU professor and co-creator of Canberra Pollen Simon Haberle said the territory recorded particularly bad results.

"Even compared to other parts like Melbourne and Sydney, and other areas in the south-east of Australia, Canberra had the highest recorded level this year for that season," he said.

The primary cause can be traced back to the La Nina period and ensuing wet weather, which stimulated grass growth throughout spring.

Mr Haberle said grass pollen had dropped off as expected in mid-late January, but the period during which tree pollen is present has extended.

IN OTHER NEWS:

"We have a short period of tree pollen in the air which is also allergenic and that includes the elm trees - the Chinese elms - and Casuarina or she-oaks."

"Those two trees, normally we see them only lasting a couple of weeks around mid-February, but this year, that period of tree pollen has actually extended for at least four weeks."

He said the abnormally long season of tree pollen was due to a very warm, late summer and early autumn.

"This has allowed some of the trees to actually produce flowers and pollen for a much longer period."

"So all this is telling us ... with global warming increasing warmer temperatures that can potentially extend the period of hayfever suffering."

Year-round surveillance was increasingly significant for this reason, Mr Haberle said.

"It's really important that we do keep on monitoring the pollen so we can get a better understanding of how it's changing through the global climate change era."

Asthma Australia advised anyone dealing with asthma and hay fever symptoms, to reevaluate their management plans.

"With this spike in grass pollen in the air, many of those with poorly controlled asthma are at risk of asthma flare-ups, which can lead to hospitalisation and sometimes it can be fatal," Asthma Australia CEO Michele Goldman said.

"Asthma flare-ups cause nearly 39,000 hospitalisations annually, and our message for people with asthma is to consult with their doctor to help manage their condition all year round, to reduce the risks from unexpected events like this."

More information on asthma management is available here.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: