The siren sounded repeatedly for the second, much larger, fire, which needed more firefighters who had not received pager alerts, he said.
Williams, who has nearly 40 years' experience, explained this in a Facebook post, apologising to anyone who was disturbed.
Williams told the Bay of Plenty Times he would not say who had complained, out of respect for their privacy, but said he had spoken to them and explained the need for the siren.
He hoped that would help but said he was frustrated with some who appeared to remain ignorant or selfish about the siren.
Te Puke Fire Station was volunteer-run and Williams said the siren was the only reliable alert system, as pagers could sometimes not work or be missed. The siren also offered audible reassurance to people desperately needing it, he said.
"If we were asked, or instructed, to turn the siren off we would be vigorously resisting that," he said.
"We are concerned, we don't want our siren turned off at night."
Many people replied that Williams had no need to apologise, and perhaps the people having trouble sleeping should buy earplugs.
Sarah Tutemahurangi-Brickland posted: "No need to be sorry!!!! So so so thankful for the wonderful volunteers- we live on a corner just before a big straight and have had a ridiculous amount of car accidents over the last 2 years, often we are one of the first on the scene or are the ones to ring the services, it's an absolute magical sound when you hear that siren and know help is coming. We have witnessed some horrendous scenes and it's truly so scary. The relief that washes over you when you hear that siren and then help turns up minutes later is knee buckling. This is coming from a witness not a poor victim- I can only imagine what that siren sound means to them when they hear it."
A Western Bay of Plenty District Council spokeswoman said the council had no record of requests about the fire siren so far this year.
Sirens are classified as warning devices and thus exempt from the District Plan noise requirements in all zones in the Western Bay.
Fire and Emergency NZ region manager David Guard said they understood some residents' concerns with siren use, but refused to specify which stations.
Guard said a siren ensured volunteers working in noisy environments heard the callout.
"While we have other technology to alert volunteers, we like to use at least two of these methods (siren and pager) to ensure our volunteers are alerted.
"Some of our sirens are operational 24/7, this is to ensure response capability. "We understand sirens may inconvenience some people who work different schedules or have young family members – we apologise for that."
SIrens were an "important response tool" that ensured volunteers could get to emergencies in good time to help people in need, he said.
About 370 stations across New Zealand use sirens. Monday morning's fire involved a stockpile of pipes at Lawrence Oliver Park on No. 1 Rd.
A police spokeswoman told the Bay of Plenty Times the construction site and pipes were part of a Tauranga City Council water supply project.