The ministry asks the Riga Municipality to prevent people from climbing the hill, also known as Ušakovs' hat referring to Riga mayor Nils Ušakovs.
An Environment Ministry press release notes that people can still freely access the trash mound, circumventing a five year ban on public access to the mound.
Winter saw hundreds of people tobogganing on the mound with the gates thrown open, despite signs saying entry was forbidden. The mayor even tweeted about the imminent opening of the hill to the public.
"It's still a dump and you can't be on the mound for at least five years or when monitoring results say it's no longer a threat to human well-being and life," the Environment Ministry release says, adding that the Riga City Council puts taxpayers at risk as EU funds, which might have to be repaid, had been used to construct an apparently ineffective fence around the former garbage dump.
The city council had periodically asked the Environment Ministry for permission to install park seats and picnic tables on the hill, however the ministry had denied the requests citing safety concerns as pressure might affect groundwater flowing under the former dump.
The ministry wants the mound to be left intact for at least five years and then monitored for another twenty.
The video below shows a bird's eye view of the site.