Sydney Airport passenger numbers take off

Sydney Airport has posted its strongest growth in passenger numbers in 12 years, with 21 million passing through the airport in the first six months of 2017.

A 7.7 per cent increase in international flyers from the same period in 2016, and a 1.3 per cent improvement in domestic travellers, helped Sydney Airport's half year profit rise four per cent to $167 million.

The strongest growth in overseas passenger numbers came from Asian markets including China, India, the Philippines, Indonesia, Japan and Vietnam.

Chief executive Kerrie Mather said an improved business performance, plus a positive outlook for the second half of 2017, allowed the company to forecast an 11 per cent in distributions to investors to 34.5 cents for the full year.

Revenue improved in all divisions of Sydney Airport's business in the first half of 2017 - aeronautical services, retail, parking, and property and car rental.

But growth was most modest in parking, at 2.2 per cent, to $77.1 million.

The company said more passengers are travelling to the airport by train, and there has been an increase in the use of limousines and ride sharing services such as Uber, plus slower growth in the number of Australians travelling overseas.

Ms Mather, who will retire from the role once a successor is appointed, said the number of passengers choosing to pay and park at the airport is relatively small, but the airport is seeing improvements due to new options like online booking.

"As we continue to roll out more products for the people looking to park at the airport we are actually seeing an improvement in the performance," she said.

The company expects property revenues to be boosted in the second half of 2017 by the opening of its new Mantra hotel and its $34.5 million purchase of an Ibis airport hotel in July.

PASSENGER GROWTH BOOSTS SYDNEY AIRPORT'S PROFIT:

* Net profit up 4.4pct to $167m

* Revenue up 7.9pct to $714.2m

* interim distribution up 1.5 cents to 16.5 cents, unfranked