Australian government environmental committee report warns that thousands of miles of coastline are under threat from rising sea levels and suggests banning people from living in vulnerable areas

Beach culture is as much part of the Australian identity as the bush and barbecues, but that could have to change according to a government report that raises the unsettling prospect of banning its citizens from coastal regions at risk of rising seas.

The report, from a parliamentary climate change committee, said that AUS$150bn (£84bn) worth of property was at risk from rising sea levels and more frequent storms. With 80% of Australians living along the coastline, the report warns that "the time to act is now''.

Australia has no national coastal plan despite the prospect of losing large swaths of coastal land as each centimetre rise in sea levels is expected to carve a metre or more off the shoreline. If sea levels rise 80cm by 2100, some 711,000 homes, businesses and properties, which sit less than 6m above sea level and lie within 3km of the coast, will be vulnerable to flooding, erosion, high tides and surging storms.

It argues that Australia needs a national policy to respond to sea level rise brought on by global warming, which could see people forced to abandon homes and banned from building at the beachside, according to the committee on climate change, water, environment and the arts.

The prime minister, Kevin Rudd, said the report was a reminder that "Australia has more to lose through continued inaction on climate change" than most other countries. "The real cost for Australia of continued inaction on climate change is deep and enduring and damaging to our economy and damaging to the nation's environment," Rudd said.

Skirmishes between residents and local councils are already erupting up and down the coast over erosion by the sea. On the far north coast of New South Wales, the state government has intervened to allow residents in the Byron shire council to build seal walls to protect their homes from rising sea levels. A similar battle is being waged further south at Taree. Meanwhile insurance companies are refusing to insure properties in seaside towns.

Among the report's 47 recommendations are that the government could consider "forced retreats", and prohibiting the "continued occupation of the land or future building development on the property due to sea hazard".

Some members of the conservative Liberal-National party coalition, which voted down the Rudd government's carbon emissions trading scheme earlier this year, remain sceptical that a problem exists. Liberal MP Tony Abbott, a senior member of the coalition and leadership contender, said there was no reason for alarm. "When it comes to rising sea levels I'm alert but I can't say that I'm particularly alarmed. The fact is that sea levels have risen along the NSW coast by more than 20cm over the last century. Has anyone noticed it? No they haven't. Obviously an 80cm rise in sea levels would be more serious but I'm confident that we have the resources to cope," Abbott told ABC news.

How much sea level could rise this century with increasing temperatures is an open question. The much-quoted 2007 report from the Intergovernmental Panel on Climate Change said it could be up to 59cm, though warned that higher increases could not be ruled out. The IPCC said not enough was known about the way ice sheets break up to put a reliable figure on their contribution. Some estimates predict a 1-2m rise by 2100.

The Australian government report, Managing Our Coastal Zone in a Changing Climate, followed an 18-month enquiry. It said the country's current coastal management policy is fragmented, and authorities need to adopt a national policy to coordinate new coastal building codes and relocation and evacuation plans. Australia must examine the legal liability and insurance cover associated with property loss and damage due to climate change, improved early warning systems for extreme seas, and work to prevent the spread of tropical diseases such as dengue fever, it added.

"The key message that emerged from the inquiry is the need for national leadership in managing Australia's coastal zone in the context of climate change," Jennie George, a government MP and committee chair, said in launching the report on Tuesday. "This is an issue of national significance."

The sub-tropical state of Queensland was the most at risk, with almost 250,000 buildings vulnerable. Next was the most populous state, New South Wales (NSW), with more than 200,000. Coastal flooding and erosion already costs NSW around AUS$200m (£112m) a year.

The report called for a national policy which could see government authorities prohibit occupation of land or future building development on property due to sea hazards. It called for building codes, including cyclone building codes, to be revised to increase resilience to climate change.

Alan Stokes, the executive director of the Sydney-based National Seachange taskforce, which represents coastal community councils across Australia, says banning development in certain areas is necessary. "There's no doubt Australia will remain and continue to be a coastal community," he said. "But we may have to be a bit more considerate about which parts of the coast we develop further and which ones we don't."