The airline is ordering 48 of the newest widebody aircraft, 22 of them the A350-900.
Smith said Cathay next year was expecting delivery of 12 of the new planes which have a list price of US$304 million.
The new aircraft would have 38 business-class seats compared to 26 in the A340, 28 premium-economy seats (no change) and 214 in economy (three more).
"The big increase is in the business-class cabin. We have a lot of confidence in the premium market."
Smith said the business class seat would be an enhancement on what is on Cathay's newer Airbus A330s and Boeing 777s and a "significant improvement" on the A340 seat.
Passengers would have a dual screen experience whereby the traditional handset will be a small touch screen.
"You'll be able to watch a movie on the main screen and able to check the progress of the flight on the other."
There would be an all new premium-economy seat and while the economy seat would be improved, those in the back of the plane would benefit from the latest inflight entertainment system.
The aircraft is wifi capable and Smith said the airline would run trials to ensure systems are robust.
"We want to make sure it is similar to what they get at the office or at home.
"We'll be conducting trials before rolling it out."
The A350 is a rival to Boeing's 777s and 787 Dreamliner.
Qatar Airways this year became the first airline to operate the A350.