The green Tory campaigner said Britain’s environment protections “still need to be strengthened” rather than undermined by drive to cut red tape.
“There are plans for several dozen investment zones, and we certainly need to make sure that they don’t override basic environmental protections,” said Mr Johnson.
He added: “I can understand the mad dash for growth. The mad dash for growth may seem essential now – but come 10 years from now, when we find that some of our key wildlife sites, our key landscape areas have been put at risk we’ll think differently about it.”
Ms Truss’s chancellor Kwasi Kwarteng has promised investment zones where planning rules will be hacked back to encourage development – sparking fears from environmentalists of “deregulation on steroids”.
The PM has also promised a new bill to axe up to 1,500 items of so-called retained EU law – on workers’ rights, the environment, data privacy and much more – by the end of 2023.
Mr Johnson told The Independent he was worried it could put many parts of the EU’s Habitat regulations – which protect wildlife – at risk.
“These are crucial, crown jewel regulations, and I don’t want to see them threatened in any way,” said the former PM’s father.
Mr Johnson said the moves to ditch retained EU legislation by a “sunset” deadline “needs to be looked at very, very carefully”, adding: “We must not throw out the baby with the bath water here.”
The campaigner added: “Without the backstopping of UK legislation – that is the worry, that this sunset clause push, this artificial deadline at the end of 2023 – will put them at risk.”
Urging the Truss government to uphold the policies embarked upon when his son was at No 10 to achieve net zero carbon emissions by 2050. “Stick to the plan – you’ve got to for the sake of the climate,” Johnson Snr said.
The new environment secretary Ranil Jayawarden used his conference speech on Monday to say the Department for Environment, Food and Rural Affairs (Defra) would stop being a “regulatory department” and become a department for economic growth.
And Mr Kwarteng told the Tory conference that the government would review, replace or repeal retained EU law “holding our country back”.
But Ms Truss’s government has watered down her Brexiteer-pleasing campaign pledge to scrap all EU rules by the end of next year – allowing some to remain in place until 2026.
A statement from business secretary Jacob-Rees Mogg said the bill “includes an extension mechanism for the sunset of specified pieces of retained EU law until 2026”.
He added: “Should it be required, this will allow departments additional time where necessary to implement more complex reforms to specific pieces of retained EU law.”
Meanwhile, Mr Rees-Mogg said he would be “delighted” to have his own back garden drilled for shale gas as he defended the government’s decision to lift the ban on fracking.
The business secretary suggested that he would welcome drilling on his Sommerset land because of the “cash” royalties he would expect fossil fuel companies to offer.
But he dismissed the idea of local votes to gauge support to allow fracking to go ahead. “I don’t think local referendums are necessarily the right idea, turnout in local referendums could be very low,” he said.