A fire communications spokesman said everyone was evacuated and firefighters went in to investigate but it was an accidental activation.
Holmes Group managing director Ryan Holmes said they couldn't have asked for a better first weekend.
"It went really well. There were 5000 to 6000 people attending on Saturday."
Lynmore resident Tracey Campbell took along her two daughters aged 5 and 7 on Saturday.
"They were pretty stoked, running around everywhere checking out everything. They were very excited."
Mrs Campbell said she told the girls they could choose one attraction to attend, with the plan to try a new one each visit.
"They chose Chipmunks [Playland and Cafe]. We were there for two hours and they had a ball...they wanted to go back on Sunday."
She said she thought it was awesome for Rotorua and she was blown away by the number of people there.
"There's so much on offer, there's so much stuff there...it'll be awesome on wet days for the kids."
What's at Motion Entertainment:
* Dialled Indoor tramp park
* Strike Zone tenpin bowling
* Megazone laser tag
* Timezone
* Escape Masters
* Lumberjax mini golf
* Chipmunks Playland and Cafe
* Revived Bistro