British citizens travelling or studying abroad for more than three months are being refused benefits on their return under new rules designed to crackdown on benefit tourism from eastern Europe.

Changes to the habitual residence test, designed to make it harder for European Union migrants to claim benefits, mean UK citizens who have been abroad for an extended period cannot claim jobseeker's allowance (JSA) for the first three months after their return.

It means that people who travel for more than three months – including gap-year students, graduates and people taking career breaks – are being denied JSA to help them while they find a new job.

The new rule came in on 1 January, the same day it became legal for migrants from Romania and Bulgaria to enter the UK on work visas. In a government-issued statement on the new rules, the work and pensions secretary Iain Duncan Smith said: "The British public are rightly concerned that migrants should contribute to this country, and not be drawn here by the attractiveness of our benefits system."

However, in attempting to combat predicted "benefit tourism" from eastern Europe, the government has made it impossible for UK citizens returning from abroad to claim as well. Yvette Cooper, shadow home secretary, said:, "British-born citizens who have been travelling, doing internships or living abroad temporarily shouldn't be treated in the same way as those coming into our country for the first time.

"Habitual residency rules should be about making sure people who are new arrivals to the UK, and have not yet made any contribution or commitment to this country, do not claim benefits they are not entitled to. British citizens are in a completely different situation, and the government should recognise that."

Rosie Smith, 24, and her boyfriend Alexi Dimond, 29, are both from Sheffield and returned to the country in March after almost six months living and doing voluntary work in Thailand. Smith had been in the same city since she was born. She wanted "a bit of a change", she said: "I had been in Sheffield my whole life. I just wanted six months not in Sheffield."

Alexi Dimond and Rosie Smith, from Sheffield, who were given a leaflet on Emergency Help that he used to hand out to asylum seekers. Photograph: Christopher Thomond

Smith saved money from her job as a nursery nurse, while Dimond worked in administration at an NHS dental hospital. When they got back, they wanted to look for work immediately and registered with the Jobcentre the next day. Dimond claims the person asking him questions for the habitual residence test was "very apologetic" for even making him undergo it.

He was told he was not, under the new benefits rules, considered habitually resident in the UK and would have to wait three months before claiming JSA. "I thought it was outrageous really," he says, "I've contributed tax for the last six years working for the NHS. I think it's ridiculous I'm not entitled to anything." He now had no money at all, he said, and was relying on friends for food. Smith has moved back in with her parents.

Alongside his job, Dimond had done voluntary work with asylum seekers for five years before leaving the UK. When enquiring at the Jobcentre how he was supposed to survive, he was handed a leaflet entitled Emergency Help in Sheffield. It is the same leaflet he was issuing to asylum seekers before he went away. "It's basically the help you get when there is literally nothing else," he explained.

British citizens have always had to take a habitual residence test before being granted benefits, but only since the rules changed on 1 January have people been told they automatically fail for spending time out of the country.

Sam, 25, is back living with his parents in Manchester for the first time in seven years after being refused JSA on his return from a year in the Netherlands where he was doing a master's in psychological research.

Sam had hoped he would get a job as soon as he got back "but that's not the case," he said, "so I applied for jobseeker's soon after I got back."

He was taken aback to have his application for benefits turned down. "I think if you're looking for work you should get jobseeker's allowance. That's what makes sense," he said. Sam's parents are providing his food and shelter, and he is dipping into savings to travel to job interviews in London. He realises he is lucky to be cared for, claiming it is unfair on others "who don't have that support. You would think then that support should come from the government."

However, he is sympathetic to a tougherstance on immigration, agreeing that migrants "shouldn't be able to claim [straight away] if they come from abroad."

Emma Birks, 36, was a volunteer co-ordinator at a worker's co-operative in Birmingham before deciding to go travelling in south-east Asia. "I'd been putting it off and putting it off," she explained, "and then sometimes you think 'life's too short'."

Since she got back in March, Birks has had no home and has been living between the houses of "three or four" charitable friends. She has been surviving by taking handouts and using credit cards. Because of her work, she knew about the habitual residence test and never dreamed she would fail it. She describes her situation now as "a bit demoralising and humiliating.

"The whole point of jobseeker's allowance is to help you in that interim period where you're looking for work, trying to find a new start or whatever. To me, that's the whole point of jobseeker's and it's just failed me basically," she said.

Dimond agrees. When we speak, he and Smith are at the beginning of five days of agency work, stopping people in a Doncaster shopping centre and collecting surveys about the facilities. He has had to borrow the money to get to work, and estimates he already needs "about six months" to catch up on his debt, assuming he gets a job soon. "It's seriously affected my job search," he said. "I don't have money to get to interviews."

Smith thinks they are victims of statistics. The Department for Work and Pensions (DWP) "are just trying to get as many people off their system so they can make their numbers look better … so they can say hardly anyone's signing on anymore. But they're just disqualifying everyone," she said.

A DWP spokesman said: "It has always been the case that any UK national who chooses to live or work in another country for an extended period must, if they return to the UK and want to claim benefits, satisfy the habitual residence test by proving they have strong ties to the country and want to remain here.

"People who have paid enough national insurance in the UK do not have to wait for three months before claiming jobseeker's allowance." The spokesman did not respond when asked how much national insurance was enough, but none of the people interviewed were exempt from waiting three months.

The announcement of the changes in December confirmed the the introduction of the new three-month period in which people cannot claim benefits.