Melbourne Airport runway plan takes off

The $1.9 billion project is expected to increase the airport's capacity by about 40 per cent, with around 136,500 more take-offs and landings each year.

Planning maps show noise from the extra flights will be heard in Melbourne's north and west, and the airport has developed an online tool that will calculate the impact on residents at different times of day.

Melbourne Airport chief executive Lyell Strambi told reporters on Monday some suburbs may experience less noise.

"There is no doubt that additional activity does bring more noise to the surroundings, but it really depends on where you live," he said.

Melbourne Airport says the extra runway will make it easier for flights to depart and arrive on time, and prevent shutdowns in high winds.

It's also expected to attract new international airlines to Tullamarine, which will lead to more direct flights to international cities.

Passenger numbers at Tullamarine reached 37 million in 2019, and are forecast to reach 83 million by 2046.

There are still fewer flights than usual due to COVID-19, with activity on the weekend at half the usual levels.

"I think COVID has been obviously a huge impact on the travel industry here and abroad and we are still in the throes of recovering from it," Mr Strambi said.

But he said the existing two runways were nearing capacity before the pandemic, with their cross-shaped runway configuration causing congestion and delays at peak times.

The ultimate scheme for the airport, conceived in its initial planning 60 years ago, is to build four runways in a hashtag configuration.

It's estimated the new runway will create 37,000 jobs for the state and add $4.6 billion to GDP by 2046.

During construction, it will create jobs for about 650 people over the four- to five-year build.

Building work could start as early as 2023 with planes taking off from the runway in 2027 at the earliest.

The runway plans are yet to be approved by the federal government.