TRAFFIC congestion in the outer south-east was slowing productivity, and a lack of public transport services was deterring young people from taking up apprenticeships in the area, said a local manufacturers association.
South East Melbourne Manufacturers Alliance executive officer Paul Dowling said clogged roads inhibited the flow of people and goods.
"The feedback that we get from our members is that it causes a lot of frustration and even discourages people from working in the area."
In a pre-budget submission to the State Government, the Victorian Employers Industry called for greater investment in infrastructure to cope with Melbourne's rapid population growth.
VECCI chief executive Wayne Kayler-Thomson said the state needed to "move up a gear in terms of the scope and size of our infrastructure commitments".
"Growth in this area has been phenomenal. There has been a good demand for locating here and EastLink will help free up that transport flow."
He said investment in public transport infrastructure was particularly important for young apprentices, otherwise "they can't get around".
The State Government said it had a $10.5 million plan for transport projects, including the Dandenong rail triplication.