RENEE Lockwood got a day off work yesterday, but she wasn't happy about it.

The 22-year-old Toowoomba child care worker was stranded at Rockhampton Airport for three hours as her Qantas flight to Brisbane was delayed.

Renee eventually made it to her destination after a crew fixed the plane's technical problem.

But she was lucky – tens of thousands of other passengers faced delays of up to days after another ash cloud from Chilean volcano Puyehue-Cordón Caulle returned to disrupt air travel across the country.

This included the Federal Government's climate change adviser Ross Garnaut, who was forced to abandon plans to speak in Rockhampton today.

He was due to speak to more than 80 people at Belmont Research Station near the city.

Airservices Australia said the cloud was much larger than last week's plume.

Tiger Airways yesterday cancelled two flights between Melbourne and Rocky as the ash continued to disperse over southeast Australian airspace.

A Qantas Rockhampton to Sydney flight was also cancelled.

Rockhampton Airport confirmed six flights to Sydney and Melbourne during the rest of the week were in jeopardy.

Qantas also cancelled 73 domestic flights to and from Adelaide, Canberra and Sydney, and six trans-Tasman flights.

And Virgin Blue closed their Adelaide, Sydney, Melbourne and Mildura routes.