AS the debate hots up over how best to monitor the health aspects of prostitution in Hongkong, Keeping Posted suggests that the authorities could do no worse than check out the system introduced some while back in South Korea.

Women engaged in the world's oldest profession in Seoul are required to carry health ''passports'' on which they get a stamp each month to indicate their health status after a check-up at a government clinic. A blue stamp indicates a clean bill of health, while a red stamp denotes the reverse.

To drive the message home, they even devised a colourful slogan that loosely translated something like: ''If it's red don't get into bed. But if it's blue it's up to you.'' But with all the foreign call-girls supposedly operating over here, the opening line of ''Let's see your passport?'' might well cause some confusion.