Papua New Guinea's opposition says government-driven changes to the Environment and Conservation Act have sold out the rights of landowners.
The amendment to the Act which rules on major resource projects would prevent law suits being filed against environmental destruction and damages caused by resource projects.
Environmentalists and the trade union movement say the government rushed the amendment through last Friday without giving much notice or room for debate on the full effects of the legislation.
The opposition's Bart Philemon says the amendment should be withdrawn because it clearly favours the interests of developers at the expense of landowners.
"This amendment virtually excludes landowners after the secretary for environment has satisfied himself that environment issues have been addressed and he has issued a certificate (or approval) to the interested parties. It virtually cuts out the continuing interests of landowners."