Supermarket customers here could soon have to pay for plastic bags, following in the footsteps of other cities that impose such a charge.

The Sunday Times has learnt that Singapore's four main supermarket chains - FairPrice, Dairy Farm Group, Prime Supermarket and Sheng Siong - are in discussions to see if they can agree on implementing a plastic bag surcharge.

If an industry wide agreement is reached, shoppers can expect to start paying for plastic bags by the middle of next year. The price of each plastic bag could be between five cents and 10 cents.

The discussions came about after environmental group Zero Waste Singapore in June last year called on the Government and local businesses to introduce a levy on the use of plastic bags, primarily as a disincentive to shoppers to use them.

Some 822,200 tonnes of plastic waste were generated last year, but only 7 per cent was recycled.

Singapore used about three billion plastic bags in 2011, according to a 2013 study by the Singapore Environment Council. "It is likely that the number has risen as the population of Singapore has increased," noted its spokesman last week.

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Plastic bags can be placed in recycling bins if they are not contaminated with food waste. But non-recycled plastic bags, whether or not biodegradable, are all incinerated.

The burning of plastic produces carbon dioxide, which contributes to the warming of the planet.

Excessive use of plastic bags could also clog up Singapore's only landfill, on Pulau Semakau. Ash residue from incineration is sent to the landfill, which is filling up at a rapid rate and may become full as early as 2035, a decade earlier than projected.

If the move to impose a plastic bag levy is adopted by the supermarket chains, it could have an appreciable impact as they have a huge piece of the shopper pie.

Places such as Penang and California have plastic bag surcharges.

A spokesman for the National Environment Agency said it supports ground-up efforts to encourage consumers to use reusable containers and bags, and has been engaging supermarket operators on this issue.

The supermarkets would not be drawn to comment specifically about the voluntary agreement. But Prime, Sheng Siong and Dairy Farm Group emphasised the need for all retailers to adopt a plastic bag charge for there to be an impact.

FairPrice director for corporate communications and brand Jonas Kor noted that a surcharge could pose hardship for lower-income groups. "We, however, continue to assess the feasibility of plastic bag reduction measures and remain open to any new initiatives and potential partnerships, such as the BYO (Bring Your Own) Singapore campaign, to encourage this positive industry trend," he said.

Consumers said they would prefer not to be charged for plastic bags, though a levy would spur them to look for alternatives. Dental assistant Lai Xian Ying, 32, does not mind paying a small fee. "We need to do our part to save the Earth,"she said.