The airport last financial year began construction at its business park on warehouse and logistics facilities for TNT, Toll Group and DHL, as well as a new self-serviced apartment complex for the Quest group.

Capital expenditure for 2013-14 increased by 67 per cent, CEO Chris Woodruff said.

The 360 hectare business park has about 26 freight facilities and will be one of the biggest in the state when complete.

"Next year alone we expect to invest around $700 million as part of sustained 10-year investment period," Mr Woodruff said.

Much of that outlay will be spent on a new terminal and road links to cope with growing passenger numbers.

"Asia continued to drive our international growth with China holding its place as our most important long haul market. Elsewhere in Asia, Singapore, Japan, Malaysia, Hong Kong and Taiwan all grew by an extraordinary minimum of 20 per cent," Mr Woodruff said.

The new $500 million domestic Terminal 4 which will house Jetstar, Tiger and Rex airlines includes a ground transport hub for collecting and dropping off passengers, vehicle parking and is expected to be finished by mid 2015.

"We're probably one of the biggest construction sites in Victoria and will be for the next 10 years," the airport's property and construction executive Linc Horton said.

The rollout of Airport Drive, a new entry for the airport, will connect it directly with the M80 Western Ring Road.

Plans are also in place for the four construction stages of an elevated loop road to ease traffic congestion.

Mr Horton said the airport's road network was at capacity and it would struggle to cope with extra passengers without additional work.

The total passenger numbers passing through the airport grew by 4 per cent last financial year to 31 million. International visitors increased by 9 per cent to 7.75 million, while domestic flyers grew by 2 per cent to 23.3 million.

The Skybus service takes about 10 per cent of passenger traffic, Mr Horton said.

Despite suggestions otherwise, the airport was supportive of a new rail link which would take about 15 to 20 per cent of passengers. "We want the rail, we support the rail," he said.

Tullamarine was the only major Australian airport to increase air freight imports and exports.  Live exports of merino breeding rams to China increased more than 3000 per cent for the year.

Because the airport was curfew-free it had increased freight capacity ahead of others.

"A lot of it is perishable goods, things like asparagus, meat, breeding stock and medical products," he said.

About 80 per cent of freight was shifted on passenger airlines.