Brian Vaughn, whose daughter goes to junior school with April, described her as a "lovely little girl". He said: "Everybody just wants her back, really.
"Whatever we've got to do, we'll do it. We're just hoping for the best, that she's closer rather than further away."
Machynlleth town councillor Michael Williams was among those taking part in the search. He said local people were "stunned".
"I've lived here all my life and I've never heard of anything like this before. The family must be devastated, and I hope to goodness the little girl is found without any huge delay.
"It just shows a town like Machynlleth when something does happen the people are out here, they've been out on the streets earlier looking - and here we are now, we will do whatever the police advise us to do to help look for this little child."