Qantas flights to Darwin will resume tonight after Cyclone Monica bypassed the city.

Australia's most northerly city, devastated by Cyclone Tracy in December 1974, won a reprieve today as Monica changed direction, bypassed Darwin and weakened significantly.

Qantas said its aircraft would resume flying to Darwin this evening, after a dozen scheduled flights were cancelled due to the cyclone danger.

"All Qantas (flights) scheduled to and from Darwin will be back on line as of 1915 (AEST) this evening," a spokesman said.

"The first Qantas flight back to Darwin will be QF1942, Alice Springs to Darwin. As of that flight, all our scheduled services are as normal."

The airline cancelled eight flights today and four yesterday as Cyclone Monica bore down on the Top End.

Passengers on cancelled flights had been given a choice of deferring their travel or bypassing Darwin as a stopover point, the spokesman said.