Natural Resources and Environment Minister Varawut Silpa-archa on Tuesday suggested Khao Yai National Park officials go to the post office and mail a load of rubbish to litterbugs.
Mr Varawut was being scathing in his criticism of tourists, who rented campsite space at the park last weekend.
"The park provides rental tents and facilities to every tourist," Mr Varawut posted on his Facebook page.
"Therefore, please don't forget to put your rubbish in the bins provided before leaving, in order to avoid endangering the wild animals.
"In this case, I would post every bit of that rubbish back to those tourists as a souvenir."
Mr Varawut was reacting to photographs posted on Facebook by a user called "Chut Tang Camp" (tent camping spot).
They showed some of the rubbish that was left behind in two tents in Khao Yai on Saturday.
Officials are reported to have verified the accuracy of the post.
The Facebook post also included a photo of a parcel being loaded with rubbish and being sent back to the tourists.
The photo blurred the name of the recipient, displaying only an address in Pak Chong district, Nakhon Ratchasima.
Park officials are also reported to have lodged a complaint with police regarding the tourists, alleging they violated the 2019 National Park Act by littering Khao Yai and damaging its ecology.
First-time offenders can be jailed for up to five years and/or fined up to 500,000 baht.