Ministers are right to leave the door open to fracking in national parks because oil and gas have been exploited uncontroversially in such areas for decades, Matthew Hancock, the new energy minister, has said.

Unveiling the first new competition for onshore oil and gas licences for six years, the Conservative MP said there would need to be exceptional circumstances for shale drilling in protected countryside but people should remember that national parks cover 16% of the UK.

The government is on Monday to advertise around half of the UK to companies which want to exploit shale gas, in the first sale of new onshore licences since experts discovered the scale of the UK's reserves.

Ministers are hoping that tighter planning guidance on drilling in national parks will help see off some of the critics of fracking, who fear it will cause environmental damage.

Hancock told BBC Radio 4's Today programme on Monday: "A huge proportion of homes across the country use gas and may well be cooking breakfast on it as we speak. Having domestic and secure energy supplies in a dangerous world is a big prize, but we've got to do it in a way that is careful and that's why we've brought in stronger protections on the one hand, but also are saying yes, let's explore and see what opportunities we've got.

"There will need to be exceptional circumstances to do this in natural parks, precisely because for decades there already has been exploration for conventional oil in national parks and it's been done in a way that has not caused great controversy. And where it's being done in a reasonable way without an impact on the local environment, then we don't want to put a stop to something that's already happening that is happening uncontroversially."

Ministers are also clarifying the rules on when drilling can take place in national parks, areas of outstanding natural beauty (AONBs) and world heritage sites, following calls by environmental campaigners for an outright ban on drilling in them.

In a tightening of the guidance, the government is to ask energy firms to submit an environmental statement that is "particularly comprehensive and detailed" if they want to frack on or near protected countryside, forcing them to demonstrate their understanding of local sensitivities. It will make clear that the applications "should be refused in these areas other than in exceptional circumstances and in the public interest".

In addition, Eric Pickles, the communities secretary, is likely to make a final decision on more appeals related to protected areas over the next 12 months, instead of leaving it to the planning watchdog.

The competition for licences is likely to attract significant interest from energy companies keen to explore Britain's new-found shale reserves, particularly in the Bowland basin of the north-west, a central belt of Scotland and the Weald in the south-east. It is the first time the government has offered up areas of the UK for onshore exploration since experts confirmed the scale of the UK's shale resources and protests erupted in places from Blackpool to Balcombe about the potential for environmental damage.

Lord Ahmad of Wimbledon, a Tory communities minister, is to present the licensing round in the House of Lords, as MPs have broken up for their summer break. "We recognise there are areas of outstanding landscape and scenic beauty where the environmental and heritage qualities need to be carefully balanced against the benefits of oil and gas from unconventional hydrocarbons," Lord Ahmad is to say. "Proposals for such development must recognise the importance of these sites."

The licences are the first step towards exploration but firms would also have to obtain planning consent, permits from the Environment Agency and a sign-off from the Health and Safety Executive.

Over the weekend Hancock had said he wanted to speed up the process so companies would be able to start drilling within six months of putting in applications. He also said the guidance published on Monday would "protect Britain's great national parks and outstanding landscapes".

This promise is likely to face one of its first tests in Sussex, where a planning decision on a prospective Celtique Energie fracking site in the South Downs national park is due within weeks. The county council has rejected a separate application from Celtique in nearby Wisborough Green, just outside the national park, because of traffic concerns, which may now be appealed against by the company and end up in the hands of Pickles.

The Conservatives in particular are facing unrest on the backbenches about the prospect of fracking in rural constituencies. The government will hope that its tightening of the rules on national parks will placate local residents, MPs and green campaigners concerned about the impact of fracking on the landscape, drinking water and environment.

But the announcement met with mixed reactions. Louise Hutchins, a Greenpeace energy campaigner, said millions of homeowners have been stripped of their right to stop companies drilling under their property and now communities will face a "fracking postcode lottery".

"The government has fired the starting gun on a reckless race for shale that could see fracking rigs go up across the British countryside, including in sensitive areas such as those covering major aquifers. Eric Pickles's supposed veto power over drilling in national parks will do nothing to quell the disquiet of fracking opponents across Britain," she said.

Hutchins also criticised the timing of the announcement, saying ministers "waited until the parliamentary recess to make their move, no doubt aware of the political headache this will cause to MPs whose constituencies will be affected".

Labour reacted cautiously to the new push for fracking. Tom Greatrex, a shadow energy minister, said there were "legitimate environmental concerns that must be addressed before extraction is permitted". "Robust regulation and comprehensive monitoring are vital to ensure the public acceptability test is met," he said. "David Cameron's government must take these issues seriously rather than drawing simplistic and irresponsible comparisons with the USA."

Caroline Lucas, the Green party MP for Brighton, who was arrested for protesting against fracking in Balcombe last year, also raised concerns that there was no outright ban on fracking in protected areas.

"If this still leaves the door open to fracking in national parks and areas of outstanding natural beauty, it completely undermines the protective status that those areas have been given and renders it meaningless," she said. "Many campaigners have campaigned for decades to get national park status, and they are given for a reason. The idea that they could be offered up to the fracking firms is a scandal."

But Shaun Spiers, the chief executive of the Campaign to Protect Rural England, said the government's change in rhetoric on protecting the countryside would be welcomed. "The government has previously stoked opposition by giving the impression that it is committed to fracking whatever the consequence and however sensitive the location," he said. "If fracking is to happen, we need to proceed with great caution and with the highest possible safeguards."

The National Trust, which has previously campaigned for an outright ban, also had a positive reaction, saying it was "right that the government have recognised the concerns about fracking in special places like national parks and AONBs". However, it called for the new rules to be extended to other special places such as nature reserves and sites of special scientific interest.

Industry groups were pleased the government was finally licensing more areas for onshore oil and gas exploration, after ministers had repeatedly promised a fracking "revolution" that they claimed could reduce energy bills and boost economic activity. While there has been a huge amount of controversy about fracking, little has actually taken place on British soil beyond exploratory drilling.

The British Geological Survey last year estimated that deposits that could supply the country with gas for up to 40 years, although it is still unclear whether the cost of extracting it from the ground would be worth it.

Simon Walker, director general of the Institute of Directors, said the announcement marked "another step forward on the road towards a dynamic, productive and well regulated shale industry in the UK".

"There's still a way to go before the industry really takes off, but opening up a new licensing round while increasing safeguards for the natural environment is welcome evidence of the government's commitment to maximising the benefits of a British shale industry," he said.

Ken Cronin, chief executive of UK Onshore Operators Group, said it should be seen as a positive sign for investors that the industry was "one of the heaviest regulated industries in the UK and acts as an exemplar for the rest of Europe". Friends of the Earth's energy campaigner, Tony Bosworth, said: "Today the risk of fracking has spread. This threat to the environment and public health could now affect millions more people.

"Those who thought that fracking would only happen in other places will now worry about it happening on their doorstep.

"Fracking is increasingly politically toxic and is far from being seen as the holy grail of energy policy by those local to proposed drilling sites."