Humphreys launched the re-designed PASS card last week but admitted there would be a delay before they were compatible with scanners.
He said the devices, which are now often set as a requirement by the police in licensing reviews, should not be the exclusive method of proving age.
He said: “I remain to be convinced that they are reliable. We have had reports in the past of them refusing cards. The real problem comes when the door staff then see that as a final decision and do not use their own initiative to recognise that this person has a valid proof of age card.
“This is disappointing for the young person and for the PASS scheme and is bad news for the venue, because it’s unlikely that customer will be back.”
Tamlyn Thompson from IDscan, the country’s largest provider of electronic scanners, said the company’s systems would be able to read “the majority of cards within the next two weeks”.
Last month, Jean Irving, the co-chair of the Association of Chief Police Officers' licensing group told the PMA she wanted to see scanners at all venues which require doorstaff.
She said: “I have had operators tell me ‘it’s too expensive, it’ll ruin my business’. That is rubbish. I’ve looked into this and you are talking around £45 a week. If spending £45 a week is going to bring your business down then I would suggest you’re not suited to business.”
The newly re-designed PASS card was launched at Tiger, Tiger in Haymarket, London last week. It will now have a standardised design across the country, changing only the name of the issuing authority.