It will be mandatory for diners to return their trays and clear their table litter from June 1, the National Environment Agency (NEA) said yesterday.
Table litter includes used tissues and wet wipes, straws, canned drinks, plastic bottles and food remnants.
In an effort to help diners adjust, no enforcement action will be taken until after Aug 31. During the three months, they will only be advised to follow the rule.
From Sept 1, enforcement action will be taken against those who do not comply with advice to clean up after themselves at hawker centres.
First-time offenders will be given a written warning. Second-time offenders will face a $300 composition fine, and subsequent offenders may face court fines, which can go up to $2,000 for the first conviction.
The Singapore Food Agency will also work with NEA to roll out enforcement progressively at coffee shops and foodcourts in the fourth quarter of this year.
NEA said the move, which comes amid a public health crisis, follows years of extensive educational efforts to change the behaviour and mindsets of diners at public places.
Its deputy chief executive of public health and director-general of public health Chew Ming Fai said: "We've been talking about these clean tables since 2013, and there's been a lot of education effort that has been put out over the years."
One example is the Clean Tables Campaign launched in February.
Mr Chew said: "Following that exercise, we've seen a small uptick in terms of tray return rates from 33 per cent to 35 per cent, but unfortunately I don't think that is significant enough."
NEA will be setting up more tray return infrastructure across the hawker centres.
Currently, there are about 900 tray return racks installed across 111 hawker centres.
During the advisory period, safe distancing ambassadors, SG Clean ambassadors, community volunteers and NEA officers deployed at hawker centres will continue to remind diners to clear their dirty trays, crockery and litter.
Visual cues such as posters and banners will also be progressively put up at hawker centres.
NEA said Covid-19 has underscored the need to maintain high public hygiene and cleanliness standards, and various members of the public and institutions have called for stronger measures to raise cleanliness standards, including the use of legislation.
Clearing dirty trays, crockery and table litter will protect not only other diners but also the cleaners, who are usually elderly folk.
Mr Chew said that while enforcement efforts will not be scaled back even after Covid-19, NEA will monitor the ground situation and make adjustments accordingly.
He said: "This is a long-term goal to raise public hygiene and cleanliness levels in Singapore. Even as we tackle the current Covid-19 crisis, we believe that this measure will be something that we need to put in place for the longer term."