Numerous airlines were forced to delay scheduled flights as weather conditions prevented the majority of planes from landing until midmorning, meaning most flights were also unable to leave.

Sean Carson from the Bureau of Meteorology said visibility had dropped to 150 metres at the airport, which he described as “pretty bad”.

“That’s basically as thick as it gets,” he said.

Mr Carson said the combination of lingering moisture and a cold night, dropping to minus 1 degree, had created perfect conditions for fog.

“The cold nights and the clear skies partly caused the fog,” he said.

A spokeswoman for the Canberra Airport said five early morning flights took off as scheduled, but remaining pilots had put their flights “on hold” until the fog cleared.

She said each pilot made the individual decision about whether to take off, adding that flights were grounded "until the pilots deem it's clear enough for them".

The weather caused extensive delays and some cancellations by Qantas and Virgin, with some flights coming to Canberra turned around back to their departure point. This meant the planes needed for flights out of Canberra were not available.

The fog lifted prior to 11.30am, enabling pilots to land in Canberra.