Sydney Airport says a $500 million investment to upgrade its T1 international passenger terminal is already starting to pay dividends, months out from completion. 

A survey commissioned by the operator found 84 per cent of passengers rate the terminal improvements so far at seven or above, on a scale of one to 10.

"Even though construction is not yet complete, it is great that the feedback we are getting is so positive," airport CEO Russell Balding said.

The T1 terminal upgrade includes room for more food, beverage and retail outlets and world class shops, including Bambini Wine Room and Burberry, and expanded departures facilities.

Construction on the departures level is due to be completed in May.

©2010AAP