The letter was highlighted in a Dunedin City Council public forum by Dunedin resident Kimberly Smith, who had seen it on social media.
She said broken glass on the streets near the university was a health hazard,
"I would really like the streets more effectively and thoroughly cleaned."
Asked about the letter, OUCA director Karen Hurst said staff and children decided to take the initiative.
"Students often seem to have no idea that we are here, so it's a neighbourly letter.
"We just wanted to let them know that we're part of the neighbourhood and we share the street too," Ms Hurst said.
"Many of the kids walk along Castle St each day to get to the centre, and we often talk about taking responsibility and tidying up rubbish as something we all need to do," she said.
"So this was something they felt strongly about and wanted to follow through."
Despite the problem, staff and parents had noticed an improvement in student behaviour this year, compared to recent years.
The Dunedin City Council responded yesterday, saying cleaners worked in the university area three days a week, with extra cleaning occurring during Orientation Week.
Reports of glass or furniture dumping were also dealt with as they were reported.
"Unfortunately, the contractor cannot pick up glass in non-approved containers for health and safety reasons," a council spokeswoman said.
"Campus Watch and a newly-appointed council city custodian perform regular checks on the student area, and talked to students about rubbish issues," she said.
At the meeting, Cr David Benson-Pope called for a report on creating a special rating area, so the council could pay for extra cleaning needed because of broken glass.
