The $1 billion channel-deeping project had been approved, but Mr Garrett was reluctant to sign the environmental plan until he was satisfied it could meet strict environmental guidelines.

Mr Garrett has announced there will be some new conditions, including monitoring of water and tidal currents and no contaminated sediment must escape from the dredger.

He says the environmental management plan sets strict limits and if at any time they are exceeded, the dredging must stop and cannot start again without his approval.

Dredging was supposed to begin last week and the Port of Melbourne Corporation has been losing $250,000 each day the giant Dutch dredging ship, The Queen of the Netherlands remains idle.

The minister actually said.

"The words that were used were that it would be silly for them to behave like that, and it wouldn't be in their best interests," she said.

"However if that's what the ports decide to do, to be contemptuous of the courts decision, our option is to take out an injunction."

These benefits include:

Expanding the port’s trade capability as a key driver of sustainable economic growth for Victoria

Increased economies of scale – more cargo in less shipping movements equal improved costs which help make Australia’s exports more competitive

The use of larger more efficient cargo ships would see a reduction in fuel consumption and reduce greenhouse gas emissions from shipping by 1.5 million tonnes

Maintaining Melbourne’s status as Australia’s number one container port and ensuring Victorian business continues accessing the widest range of regular and reliable shipping services

The creation of 2300 direct jobs during construction and 500 jobs once completed

The Australian Council for Infrastructure Development rates channel deepening as the nation’s most valuable infrastructure project, with the potential to add $14.8 billion to GDP by 2030.

It has been described as Australia's highest-priority infrastructure project, crucial for our future viability.

The dredging of Port Phillip Bay will give super-sized container ships access to Melbourne's port, but it will be a massive undertaking; more than equaivalent to digging a 15-metre wide by 2-metre deep trench between Melbourne and Sydney*.

Supporters of channel deepening, including many in Victoria's Government and business community, say the estimated $969 million project will boost exports and trade and help keep the state's economy healthy into the future.

But will the economic benefits be delivered with unacceptable environmental costs?

Detractors say authorities are failing to answer basic questions about the impact of dredging on fragile marine ecosystems.

Will toxic sediments stirred up at the Yarra River mouth turn the bay into a murky soup and cause a watery disaster?

Already the project, set to begin February 2008, is marred by controversy with an independent panel damningly critical of the Government’s first environmental assessment, while a second attempt also came under scrutiny

It has been described as Australia's highest-priority infrastructure project, crucial for our future viability.

The dredging of Port Phillip Bay will give super-sized container ships access to Melbourne's port, but it will be a massive undertaking; more than equaivalent to digging a 15-metre wide by 2-metre deep trench between Melbourne and Sydney.

Supporters of channel deepening, including many in Victoria's Government and business community, say the estimated $969 million project will boost exports and trade and help keep the state's economy healthy into the future.

But will the economic benefits be delivered with unacceptable environmental costs?

Detractors say authorities are failing to answer basic questions about the impact of dredging on fragile marine ecosystems.

Will toxic sediments stirred up at the Yarra River mouth turn the bay into a murky soup and cause a watery disaster?

Already the project, set to begin February 2008, is marred by controversy with an independent panel damningly critical of the Government’s first environmental assessment, while a second attempt also came under scrutiny