The phrase "a plastic packet" is correct and usable in written English.
You can use it when referring to a small container or bag made of plastic, typically used for packaging items.
Example: "I bought some snacks that came in a plastic packet, which made it easy to carry them home."
Alternatives: "a plastic bag" or "a plastic pouch".
And from the last compartment, the agent pulled out a plastic packet filled with 500 ball bearings.
Back in the compartment, an attendant brought a thermos of hot water and then a rubber tube wrapped in a plastic packet.
The package arrived with a sheet of dough, which was divided into tear-off buns, and a plastic packet of confectioners' sugar.
"Don't worry about the smell," I grin desperately, ripping open a plastic packet of mint three times as large as its contents.
Her pelvis was clothed in a plastic packet, fashioned into a pair of panties indicating an attempt to protect her modesty".
Before I moved to Nashville, in 2014, he gave me a plastic packet of press passes and said, "See what you find down there.
"But then if we insisted on freeze-drying them all using huge amounts of energy and sending them halfway across the planet for energy-consuming protein extraction and then decided to sell that protein in another part of the world shaped like chicken breasts in a little plastic packet – well, there's nothing sustainable about that at all".
It looks like a dance-move choreographed to the upbeat music blaring from the cellphone radio nestled in a waterproof plastic packet somewhere in her dress.
The FTA cards with the dried blood spots were stored in an airtight plastic packet and later kept in −20 °C in freezer until DNA extraction for PCR assay.
But for an ostensibly simple plastic packet, it proved devilishly difficult to redesign.
Before you can reach your hand into your rectangular plastic packet and come up with a game plan, your face is blinded with three different colors.
