The new trajectory will be "just below 9,000 nautical miles", or 16,668 km, traveled in some 17 hours, the Hong Kong company said in a statement to AFP on Tuesday.
This flight will thus be longer, in distance but not in time, than that of Singapore Airlines which connects the Asian city-state to New York and which travels 15,343 km in 18 hours.
Cathay declined to comment on why its flight path avoids Russian airspace, which it has flown through in the past.
Many airlines have canceled flights to Russian cities or are avoiding Russian airspace since the invasion of Ukraine.
Last month, Russia also closed its skies to several European countries and all UK-linked flights, in response to a similar ban imposed on them.
The Hong Kong company is currently seeking to obtain an overflight permit for this trip which will cross the Atlantic, Europe and Central Asia.
"We always have contingency routes in case of potential events or scenarios in the aviation world," Cathay told AFP on Tuesday.
The transatlantic option is more favorable than the usual transpacific route due to "strong seasonal tailwinds at this time of year," the company said.
Before the pandemic, Cathay provided three round trips between the two cities each day.
Flights to Hong Kong are now experiencing frequent cancellations due to the city's draconian health measures and lack of passengers.
Flights from the United States and eight other countries will be able to land in Hong Kong again from April 1, thanks to a relaxation of the rules against Covid-19.
On Tuesday evening, Cathay announced on its website a direct New York-Hong Kong flight on April 3, with a flight time of 17 hours and 50 minutes.
© 2022 AFP