Tourists and migrants from outside the European Union would be blocked from entering Britain if they did not hold health insurance under proposals devised by the UK Independence Party.
Ahead of its conference in London, which starts on Friday, the party has announced policy plans that would mean visas were only granted on production of insurance cover.
Migrants would be issued with an NHS number on entering the UK and their care costs would be pursued by the health service through their insurer. After paying tax and national insurance in the UK for five years they would be eligible for free medical care.
Tim Aker, head of Ukip's policy unit, said: "Such a regime would initially apply to non-EU nationals until the point that the UK could secure withdrawal from the European Union.
"This change will help to reduce the administrative burden on doctors and hospitals as health insurance would be made a condition of gaining a visa to the UK. Insurance details would then be recorded during the registration process which applies to all patients at GP surgeries and health centres.
"Currently overseas visitors, whether lawfully in the UK or not, are able to register with a GP practice. Overseas Visitors Officers are employed by hospitals to identify and then interview foreign patients in order to invoice to recover costs for people not entitled to free NHS care.
"However this is simply not happening. Many hospitals are overburdened with long waiting times and do not want to act as immigration officials while the NHS is already buckling under the weight of administration.
"Many trusts simply brush under the carpet these claims in order to cover up their liability to unpaid costs. As a result health tourism in the UK is a growing problem costing the UK taxpayer untold amounts per year.
"This is a simple and effective way of ensuring healthcare is available to all who come to Britain, as a tourist or migrant, without opening the system up to abuse. It is a long overdue step in the right direction to bringing the NHS back round to what it was set up to be; a national health service, not an international health service."