Scientists have concluded that little has been done to protect marine life since the 1992 Rio Earth Summit.
On pledges to protect key habitat and restrict the size of fishing fleets, they say progress has been "pitiful".
Their analysis is carried in the journal Science and is being discussed during final preparations for the Rio+20 summit which opens next week.
Conservationists were delighted by Australia's move to set up the world’s largest network of marine reserves.
But globally, the picture is bleak, they say.
"Our analysis shows that almost every commitment made by governments to protect the oceans has not been achieved," said Jonathan Baillie, director of conservation at the Zoological Society of London (ZSL).
"If these international processes are to be taken seriously, governments must be held accountable and any future commitments must come with clear plans for implementation and a process to evaluate success or failure."
The researchers assessed the various pledges made at the landmark 1992 Earth Summit and 10 years later at the Johannesburg World Summit on Sustainable Development.
Governments vowed to establish an ecologically sound network of marine reserves by 2012, eliminate subsidies that contribute to illegal fishing, protect critical habitat, look after the needs of local fishermen and restore depleted stocks to healthy levels by 2015.
Subsidies have not been eliminated, and illegal fishing is still a major issue in some parts of the world.
Little over 1% of the seas are protected. Two years ago, governments agreed to raise that to 10% by 2020, but the new analysis shows that at the current rate of progress, the world is off course to meeting that target.
The pledge to restore stocks to healthy levels by 2015 has also seen slow progress. European ministers meeting earlier this week voted to give themselves until 2020 to achieve the target in EU waters.
