Immigrants too often taking advantage of UK public services, says Cameron

The prime minister has accused some foreign nationals of taking advantage of British public services and said the government is looking for ways to make them pay for access.

David Cameron made his comments on a visit to Eastleigh, where Conservatives are trying to win the seat from the Liberal Democrats following the resignation of the former cabinet minister Chris Huhne.

For the third day running Cameron upped the rhetoric on immigration. On Tuesday he chaired a cabinet sub-committee of ministers who have been asked to find ways of reducing the UK's "pull factors" for immigrants, amid growing concern about the importance of the issue for voters and about achieving the government's pledge to cut net migration to 100,000 by 2015.

On Wednesday the prime minister revealed that the list of public services the government wanted to restrict included "access to justice" as well as the NHS, benefits and housing. On Thursday he confirmed that meant a crackdown on legal aid for foreign nationals. From April legal aid will not be available for immigration cases, but will continue to be paid for asylum claims and criminal cases.

Asked about how the UK, and particularly the NHS, would cope with an expected influx of people from Bulgaria and Romania when immigration restrictions are lifted at the end of this year, Cameron replied: "There's a lot more to do to make sure that while we're welcoming we don't allow people to come here and take advantage of us, because I think that does happen too often.

"We're not tough enough right now about people who come from the other side of the world who decide to use the health service: they haven't contributed their taxes, they should pay when they use the NHS."

The Eastleigh byelection is the first head-to-head battle between the two parties on the national stage since they formed their coalition government in May 2010. Huhne won the seat by a margin of fewer than 4,000 votes from the Conservative candidate Maria Hutchings.

Cameron acknowledged that the vote next month would not change the government, but the largely two-way contest is seen as a key test of how both governing parties might fare in the next general election. Political analysts are also watching for insights into how the parties will fight for separate identities in 2015.

In a question and answer session with 1,300 workers at one of the area's biggest employers, the DIY chain B&Q, Cameron appeared to offer some clues as to how the general election could be fought.

The choice of Hutchings, a local mother and campaigner who disagrees with the party leader on much of his reforming agenda, including gay marriage and abortion, was seen as significant even before the PM made the trip south from London.

Cameron appeared to reinforce this, responding to a question on the government's environment programme, another key strand of the modernisation programme, with strong words about the emphasis on the benefits of "going green" for the national economy and household budgets.

It was not a coincidence that the Labour leader, Ed Miliband, on Thursday made a keynote speech on the economy, putting squeezed incomes and living standards at the heart of the next general election.

The strong language on immigration could also be targeted at the UK Independence party, which is seen as a chief threat to the Tories' hopes of taking the seat. In the party's office in an abandoned Julian Graves shop in the town centre, Ukip leaflets and posters are dominated by the promise to "Stop open-door immigration".

An unnecessary reference to the byelection being triggered by "what happened to Chris Huhne" – who resigned after pleading guilty to asking his former wife to take speeding points for him in 2003 – reinforced the impression that Tories are trying to capitalise on the case.

The party's campaign has emphasised that Hutchings is a candidate people can trust, an image reinforced by Cameron's repeated references to how she was a "local mum" who would focus on local issues – a possible jibe at the national status Huhne enjoyed, and certainly a counter to the Lib Dem's choice of a local councillor, Mike Thornton, as their candidate.

Hutchings ended the Q&A appearance with her party leader by pledging: "I'll be an MP you can trust … who will put your issues first."