Prisca Merz, one of the founders of the campaign, said that the plan is to build a truly global grassroots movement to put pressure on world leaders. "The destruction of the planet is proceeding at such a fast pace ... soon we won't have clean air or clean water any more and our children will not have a healthy environment to live in," she said.
"I look at where we will be in 50 years and it's quite a disastrous outlook. We need to act fast. That's the beauty of this law. It is just one law, but the impact it will have on the way we do business will be enormous," she added.
In addition to the Niger Delta oil spills, Ms Merz said the law could potentially be used to punish companies over pollution caused by oil extraction at Canada's tar sands and incidents such as the 2010 Deepwater Horizon disaster.
The campaigners are looking for a signatory to the Rome Statute - the UK and most EU countries are - to put forward the idea of an international law. They would then need to convince two-thirds of the signatories - more than 80 states - to have it included in the treaty.
Dr Damien Short, an academic who has studied the statute, said an ecocide law had been "seriously considered" by the UN and was included in a draft of the Rome Statute. However, he said his research hit a number of "dead ends", one of which was the reasons behind the demise of the ecocide law.
"The only little bit we picked up was that the nuclear lobby had a hand in it," said Dr Short, who will speak at the Brussels meeting. "With the UN, you're never really fully aware of why decisions were made."
The Niger Delta is one of the most polluted places on Earth: oil spills there have been a fact of life for about 50 years. A UN Environment Programme report in 2011 found that public health in parts of Ogoniland was "severely threatened" by contaminated drinking water. In one area, an 8cm layer of refined oil was found floating on groundwater that served a number of water wells. Shell is currently being sued in the UK courts by thousands of local people from the Niger Delta over some of the spills that have contaminated the region.
A spokesman for Shell said the company took spills "very seriously", but said most in the Niger Delta were the result of "criminal activity". "There are laws in Nigeria which are designed to deal with that," he said.
- Independent