The government through the Environment ministry has said the crackdown against the use of plastic bags will be extended to supermarkets.
Environment Cabinet Secretary Keriako Tobiko said on Friday some supermarkets still pack goods for their customers in the banned product.
"We are serious on this, I have received information some supermarkets still use banned plastic bags. Let them stay warned, that anytime we will pounce on them," Tobiko said.
He said the government has also stepped up surveillance at the border points to ensure the bags do not find their way into the locals market.
Tobiko said some unscrupulous businessmen still import the outlawed product from neighbouring countries a development he added is hampering the successful fight against environmental degradation.
In Nairobi, the CS said majority of the city residents have complied to the ban.
"We have registered dramatic success i Nairobi. At the onset, we thought Nairobi people will not embrace the ban. We really appreciate their obedience and hope that spirit will continue."
The manufacture, importation and consumption of plastic bags was effected last year over environmental concerns.
Then Environment CS Judy Wakhungu said government will not turn back and reintroduce the bags which she said had highly polluted the environment particularly in urban areas.