The target was announced last week in the DoH publication, 'The NHS in England: the operating framework for 2006/7'.
But in an editorial published in the journal Sexually Transmitted Infections, sexual health specialists warned that most PCTs would be unable to meet the access target despite receiving funds earmarked for sexual health services.
'It won't happen without more money and services reconfiguration,' said Dr Helen Ward, a sexual health specialist and senior lecturer in public health and primary care at Imperial College Faculty of Medicine in London, and one of the authors of the editorial.
She said that sexual health services were lacking in many areas, citing a BBC survey carried out in October that found that just 7 per cent of clinics could see patients in 48 hours.
Another study by a large Leeds clinic suggested that some cases GUM clinics would have to boost capacity more than threefold.
Dr Ward said the lack of services was partly to blame for recent increases in rates of STIs.
'Untreated people are more likely to spread infection,' she said.
The 2004 public health White Paper Choosing Health earmarked an extra £300 million for sexual health services, but there is no way to ensure PCTs spend the funds as intended.
Baroness Joyce Gould, chairwoman of the Independent Advisory Group on Sexual Health and HIV and All-Party Parliamentary Pro-Choice and Sexual Health Group said: 'Some PCTs that find themselves in debt are not using that money to make improvements to sexual health services.'
Dr Tom Ford-Clark, a Macclesfield GP and chairman of the RCGP sex, drugs and HIV working party, said GPs could help take some of the burden of struggling clinics.
But he added that there was little incentive to do this because sexual health had not been included in the GMS revised quality framework.
Other research published last week suggests chlamydia infection rates have risen because of more sensitive tests. The study looked at more than 81,000 test results between 1992 and 2003 in Lothian, Scotland and showed that switching from a culture-based test to one using DNA amplification in 1998 raised infection rates by around 4 per cent.
Sex Trans Infect 2006; 82: 3, 24-30, 45-8