The UK government plans to allow fracking companies to put “any substance” under people’s homes and property and leave it there, as part of the Infrastructure Bill which will be debated by the House of Lords on Tuesday.

The legal change makes a “mockery” of ministers’ claims that the UK has the best shale gas regulation in the world, according to green campaigners, who said it is so loosely worded it could also enable the burial of nuclear waste. The government said the changes were “vital to kickstarting shale” gas exploration.

Changes to trespass law to remove the ability of landowners to block fracking below their property are being pushed through by the government as part of the infrastructure bill.

It now includes an amendment by Baroness Kramer, the Liberal Democrat minister guiding the bill through the Lords, that permits the “passing any substance through, or putting any substance into, deep-level land” and gives “the right to leave deep-level land in a different condition from [that before] including by leaving any infrastructure or substance in the land”.

The trespass law change has attracted controversy before, when the government decided to push ahead despite the opposition of 99% of the respondents to its consultation. Author and activist Naomi Klein said it flouted basic democratic rights. Ministers were also accused of rushing legal changes through parliament at the start of 2014, which removed the need to notify each home in an areas of fracking plans.

The new amendment permitting “any substance” was attacked by Simon Clydesdale, a campaigner at Greenpeace UK: “Ministers are effectively trying to absolve fracking firms from responsibility for whatever mess they’ll end up leaving underground. This amendment makes a mockery of the government’s repeated claims about Britain’s world-class fracking regulations. Far from toughening up rules, ministers are bending over backwards to put the interests of shale drillers before the safety of our environment and our climate.”

Tony Bosworth, at Friends of the Earth, said the amendment would allow companies to dispose of fracking fluid, often contaminated with toxic metals and radioactive elements. “The government appears to be trying to sneak through an amendment which would allow fracking firms to reinject their waste under people’s homes and businesses. Reinjection has caused countless problems in the US and you have to question how far this government will go to make fracking a reality.”

A spokeswoman for the Department of Energy and Climate Change (Decc) said: “Shale and geothermal have the potential to bolster our energy security, create jobs and growth and provide a bridge to a greener future. These changes are vital to kick starting shale and make sure it’s not delayed by one single landowner. These new rules are all part of our robust regulatory framework [making] sure public safety is always our number one priority.”

“Operators must demonstrate that where any chemicals are left in the waste frack fluid this will not lead to pollution of groundwater. The Environment Agency will not permit the use of chemicals where these are hazardous to groundwater,” she said, adding that the amendment did not change the need for companies to obtain all the necessary planning and environmental permits.

On the prospect of the new amendment being used to bury nuclear waste, the Decc spokeswoman said the amendment gave the right to put substances into deep-level land only in the context of exploiting gas and petroleum.

But Ralph Smyth, a barrister at the Campaign to Protect Rural England, said the amendment was very loosely worded and risked unintended consequences.

“This seems another example in the infrastructure bill where the rushing to remove obstacles has led to officials making it up as they go along, without thinking through the consequences,” he said. “Powers to alter deep-level land in any way under people’s houses or ‘putting any substance’ under schools or homes is surely going too far.” He noted that the bill stresses the maximum economic recovery of gas and oil and that storing waste underground as part of drilling operations would increase the economic viability of fracking.

Ken Cronin, the chief executive of fracking trade body UK Onshore Oil & Gas, said: “The onshore oil and gas industry is committed to baseline monitoring before, during and after any shale activity to ensure the highest safety and environmental standards. We need to study all of the additional amendments to the bill in detail but any amendments that do not support high environmental and safety standards will not be supported by the onshore oil and gas industry.”