Half the working population of Britain is to be banned from bringing a foreign-born wife or husband into the country under proposals being considered by the Home Office.

The government's migration advisory committee has recommended that those wishing to bring a spouse or child to live in Britain on a family visa should have a minimum salary before tax of between £18,700 and £25,700 to ensure a burden is not placed on the state. The current threshold is £5,500 after tax.

David Cameron raised the idea in a speech on immigration last month, when he said more than 70% of UK-based sponsors of family visas had post-tax earnings below £20,000 a year. "When the income level of the sponsor is this low, there is an obvious risk that the migrants and their family will become a significant burden on the welfare system and the taxpayer," the prime minister said.

The largest group of people banned from coming to Britain under the proposal would be women from India, Pakistan, Nepal and Bangladesh. Although the US ranks third in the list of countries of origin of family visas, it is thought most sponsors would qualify under the new salary thresholds. Almost 50,000 family visas are granted to immediate relatives of British residents every year.

The lower threshold of £18,700, set at the point at which somebody is no longer eligible to claim welfare benefits, would exclude 45% – about 22,500 people – from bringing their spouse or children into the country to live with them. The higher threshold of £25,700 would exclude 64%, about 33,000, from applying for a family visa.

The committee's report, published on Wednesday, said about 25% of the British population in full-time work would be excluded by the new lower limit and about 50% of the working population would be barred from bringing in their foreign-born wives or husbands under the proposals.

For those wishing to bring in a wife and two children, the minimum threshold would be set between £24,800 and £47,600. The lower earnings threshold is based on the point at which an adult is no longer eligible for benefits or tax credits, while the higher is the point at which the sponsor makes a net contribution in terms of tax.

Professor David Metcalf, the committee's chairman, said: "The current salary threshold of £5,500 seems low considering the government's desire to ensure new migrants settling in the UK are not a burden on the state. Our recommendations are made on a purely economic basis, and we recognise that family migration is not determined by economics alone. However, our analysis suggests that there is justification for raising the pay threshold."

HeMetcalf said ministers could consider taking into account other forms of wealth, such property or savings income, but it would be difficult to assess the potential earning power of a foreign spouse.

Matt Cavanagh, the associate director of the Institute of Public Policy Research, said the proposed changes were not aimed at those living on welfare benefits but could catch anyone on the average wage :

"It isn't unreasonable, particularly in the current economic climate, to ask whether, if someone is destitute or entirely dependent on benefits, they should be allowed to bring in a spouse or partner who is likely to end up in a similar position," he said. "But introducing an income threshold at £25,700, the level of the national median income, would effectively bar half the population from bringing a spouse or partner from abroad."

Cavanagh said the development was another example of immigration policy being distorted by the net immigration target, adding: "Family migration has been falling. But ministers need it to fall faster if they are to hit their target – a target which is slipping further from their grasp because of their inability to control emigration and immigration from the EU.

"We're not talking about people who are destitute or living on benefits, we are talking about people who are working and getting an average wage. If the government goes ahead with this policy, it is likely to be challenged in the courts."