Teesport is already one of Britain's busiest.
Work has begun to build one of the UK's biggest container ports on Teesside.
The first phase of the expansion work will see Teesport's container terminal increase its capacity.
Once works are complete, the port will be able to handle up to 450,000 shipping containers a year.
The project represents a £15m investment in the port, which may double in future, increasing the port's capacity to 650,000 containers a year.
PD Ports' chief executive David Robinson said, "We are delighted to see this expansion project moving forward.
"This latest investment, which will potentially involve some £29M of total investment, signifies a long term commitment to our unitised business, on the back of major growth opportunities."
The work will create around 60 construction jobs over the course of the project.
In the longer term, the project, named The Northern Gateway, will involve dredging a channel 14.5m deep a mile out to sea, to allow 300m long deep sea container vessels to dock at a new quayside, opening the North East up to new markets in the far east.
The quay will be built on the site of a former Shell oil refinery on the South bank of the Tees, which has been lying vacant for around 20 years.
Riding out the recession
Teesport suffered during the recession, as imports dropped.
As Britain went into recession, the port's expansion plans were far from certain.
Over 2008, car imports fell by 25%, though container traffic, petrochemicals and steel, the ports other mainstays, held level.
The following year, the expansion plans were delayed and by the end of May, all Teesport's 600 employees had been written to, warning of 120 potential redundancies.
The closure of the neighbouring Teesside Cast Products steelworks, a major client of the port, was a further, major blow to the company.
But by January 2011, PD Ports announced year on year growth in excess of 45 percent at the Teesport container terminals, and a deal to reopen the steelworks was all but done.
The company says it expects to see this growth continue throughout 2011.
Teesport's expansion has been planned for a decade.
Much of the port's traffic comes from recent developments by two of Britain's biggest supermarkets, positioning it as a single-site import and distribution hub for the North of England.
In 2007, Asda built a 360,000 sq ft import centre at Teesport, which now handles 100% of the company's general merchandise imports into the UK.
In Autumn 2008, work began next door on a 1.2 million square foot warehouse for Tesco.
PD Ports is also examining broader uses for its land on Teesside, including a wood burning power station and a centre of excellence for companies working in the offshore renewable energy sector.