About 50 members of Main Street Youth, a group which meets twice a week at Weston and Papakaio, attempted to set the record with 10,000 balloons donated by local businesses, three compressors, a balloon-inflating machine and human puff.
They started at 6pm, blowing up 24kg of balloons which were expected to fill most of the 346cu m space they had at the Weston Scout Den.
When they finished, helium-filled balloons were to be released into the night sky outside and a competition held to see who could pop 100 balloons and bag them the quickest.
The attempt was monitored by Oamaru police, who counted the balloons, and videotaped the attempt.
The tape will be sent to the Guinness Book of Records, along with other information for entry into the record book.
Eugen Dupu, who with wife Esther organised the attempt, said there was no previous record for blowing up balloons, so the group was seeking to set one.
It was not known how long it would take to blow up all 10,000 balloons. The first 2000 took about an hour and a-half, but the rate was improving as the night wore on.
