The National Environment Agency has clarified that the hawker-licensing rule which Environment and Water Resources Minister Vivian Balakrishnan scrapped on Monday was to deal with "zhi char" stalls.

The rule indicated that licensees who want to sell "restaurant type of dishes" must be authorised by the Director-General of Public Health to do so.

In response to media queries, the agency said on Tuesday that the rule was referring to "zhi char" dishes, which are cooked-to-order, home-style Chinese dishes; such stalls are typically found in coffee shops. Such dishes, it said, usually involve heavy cooking and stalls must have adequate cooker hoods and flues to deal with smoke and fumes, as well as space to prepare and refrigerate the various ingredients.

"Hence the licence condition required stallholders selling 'zhi char' dishes to seek NEA's approval, so that these operational requirements are addressed upfront," said a spokesman.

However, the NEA added, most upgraded hawker centres now have exhaust systems and higher-capacity electrical power, so it will be updating its licence conditions.

It did not give figures for how many stalls were authorised to sell such food.

Dr Balakrishnan said on Facebook on Monday, in response to a Facebook post by hawker-stall holder Daniel Goh, who runs craft beer stall The Good Beer Company in Chinatown, that the rule was "archaic" and that he had ordered NEA to scrap it.

Last Friday, Mr Goh highlighted the "onerous" rule which he said was "restricting innovation" and was unclear.