Airlines cancelled flights to regional towns on Tuesday, including to fire-ravaged areas on the NSW South Coast, due to bushfire smoke making it too dangerous to fly.

Qantas and Virgin Australia cancelled one return service each between Sydney and Albury on the NSW-Victoria border because of reduced pilot visibility.

Regional Express (Rex) cancelled all flights to Cooma in southern NSW on Tuesday, and was struggling to operate into Merimbula and Moruya on the NSW South Coast.

None of the three flights from Sydney to Merimbula were able to operate on Tuesday, with two flights taking off but forced to turn back to Sydney when they missed runway approaches due to low visibility.

Several flights in and out of Canberra Airport were cancelled on Sunday due to bushfire smoke obstructing visibility.