Tens of thousands more infertile couples could be entitled to free IVF treatment on the NHS from later this year, but budget shortfalls mean many are likely to find themselves excluded.

Cancer patients, women up to age 42 and same-sex couples will benefit from proposals by the National Institute for Health and Clinical Excellence (Nice).

Some people with infectious diseases such as HIV and hepatitis, and those unable to conceive naturally because of a disability or impotence would be also included within the NHS remit for the first time.

The NHS spending watchdog launches its new draft guidance today, which takes account of medical and scientific advances, and changing social attitudes over the past eight years. The 2004 Nice guidance recommended three courses of IVF for women aged 23 to 39 who had been unable to conceive for three years. Now women aged 40 to 42 will for the first time be offered one cycle.

But the impact will be limited by the fact only 40 per cent of the 45,000 women who undergo IVF annually are covered by the NHS, according to figures from 2010 by the Human Fertilisation and Embryology Authority.

Most fertility experts welcomed the new proposals but urged caution about the financial impact as NHS trusts grapple with difficult spending decisions. Adam Balen, speaking for the British Fertility Society, said: "Many treatments are simple, cheap and effective and even the most hi-tech IVF therapies can be provided in a cost-effective manner."