Oxfam believes Pacific nations could come under undue pressure at Copenhagen as negotiations become increasingly tense.
The summit in the Danish capital has seen discussions brought to a halt by African nations and Tuvalu over efforts to secure a legally binding agreement.
The Executive Director of Oxfam New Zealand, Barry Coates, says his organisation has already seen heavy handed tactics being brought to bear on developing nations during trade negotiations:
"and we've heard some stories about that and we're very worried that small and developing nations will be put under unfair pressure in these negotiations and bully really is antithetical to this issue where the survival of the planet and the survival of millions of people is at stake."
Mr Coates says the gathering of more than a hundred national leaders at the summit later in the week is an unrivalled opportunity to secure some sort of agreement