A legal campaign group is planning a judicial review against the UK government’s new planning bill, arguing it will result in a weakening of environmental protections which were fought for and created over decades.

Wild Justice is calling on the housing minister, Angela Rayner, to correct a parliamentary statement in which she told MPs the bill, which applies mainly to England and Wales, would not reduce the level of protection. Her words were echoed in a letter to the Guardian from the nature minister, Mary Creagh, who stated it did not repeal habitat or species protections or give a licence to do harm.

The group sent Rayner a pre-action protocol letter on Monday calling on her to “correct the parliamentary record” to make clear that her statement about environmental protection in the bill was not correct. If this does not take place, they will apply for a judicial review.

Wild Justice has produced a legal opinion stating the bill would weaken existing environmental protections, with a key factor the removal of the requirement to be sure beyond reasonable scientific doubt that a development would not have a negative impact on a protected site. Instead developers will be allowed to pay into a nature restoration levy scheme in an attempt to mitigate any environmental harm elsewhere. There is no guarantee any environmental improvements would be in the same locality or even in the same county. Campaigners have argued it is impossible to replace an ancient woodland or a chalk stream elsewhere.

The Office of Environmental Protection, the government’s post-Brexit watchdog, also warns the draft of the legislation would remove safeguards for nature and put protected sites at risk.

Chris Packham, co-director of Wild Justice, said: “Good people fought long and hard to put proper wildlife protection into law. And it helped, but hasn’t stopped the relentless decline of the UK’s biodiversity. And now, in a time of absolute crisis, we need to save every last tree, bird, butterfly or bug.

“So how do the government think it’s going to if they smash those laws up? … I really hope they rein it in and bow to the love, passion and determination of a nation of animal lovers.”

Ministers argue the new bill will speed up housing developments and large infrastructure projects by allowing developers to avoid the long delays in meeting environmental obligations at the site of their project, by paying into the fund (NRF) which will be used to create environmental improvement elsewhere.

But last week the government’s own impact assessment revealed officials have very little evidence that nature obligations are a block to development.

The bill is being debated in committee in parliament on Monday, where several amendments have been suggested.

Dr Ruth Tingay, co-director of Wild Justice, said: “It’s important that the secretary of state corrects her statement on the environmental ramifications of this bill because to continue to portray it as a ‘win-win’ for nature and people is inaccurate and will mislead MPs into voting for something that is likely to have catastrophic consequences for protected species and habitats.”

Ricardo Gama, of Leigh Day solicitors, who are representing Wild Justice, said the government had told MPs to decide whether the “growth at all costs” agenda was worth trashing hard-fought environmental protections. “They they can only do that if they clearly understand what the bill entails,” he said.

The Department for Environment, Food and Rural Affairs has been approached for comment.