Video report by ITV News Correspondent Paul Brand
The plastic bag charge is set to rise to 10p and be extended to every shop, according to reports.
Theresa May is expected to announce the changes as part of plans to tackle plastic pollution, the Daily Mail and Telegraph have reported.
Currently shops that employ more than 250 people have to charge at least 5p per bag.
Under the new measures, the fee would reportedly double to 10p and include all retailers.
Disposable carrier bags issued by the seven biggest supermarket chains have declined by 86% since the charge was introduced in 2015, official figures showed.
Donations from the bag levy to good causes amounted to over £58.5 million, based on figures from two-thirds of the retailers who voluntarily reported the information.
Ministers also previously announced an intention to ban the sale of plastic straws, stirrers and cotton buds and plans for a deposit return scheme to increase recycling rates of drinks bottles and cans.
A consultation on using the tax system to combat waste is considering measures such as the “latte levy” on coffee cups.