The smoke haze from NSW bush fires has claimed another race meeting with the provincial program set down for Hawkesbury abandoned.

Racing officials made a mid-morning decision not to proceed with Thursday's meeting because of deteriorating air quality.

"Heavy smoke is now present at the course and in the interest of the welfare and safety of horses and participants the meeting has been postponed," Racing NSW said in a statement.

Poor air quality also forced the cancellation of the last five heats at the Warwick Farm barrier trials on Thursday

It was the second time this week a Warwick Farm trial session has been abandoned because of the smoke haze with just two heats run on Tuesday before the remainder had to be called off.

A race meeting scheduled for Taree on Tuesday was also lost to the smoke haze, emanating from bush fires burning in NSW.

Andrew Adkins rode in four of the six heats held at Warwick Farm on Thursday and said the air quality was "terrible".

"I'm asthmatic so it affects me a bit more than a normal person but it (smoke) was pretty savage," Adkins said.

"You could taste it."

The decision to abandon the Hawkesbury meeting left Scone to host the only racing in NSW on Thursday.