"We could smell smoke as we were approaching the station and we thought it might still be coming from the other fire," said Mr Knight, who is also a qualified firefighter.
"Then when we got closer, we could see the glowing embers making their way up the door jamb.
"After we put it out we went inside the garage and we could feel the residual heat. The station itself was full of smoke.
"The whole place had the potential to go up in flames if we had got there any later."
An examination of the police station and recycling centre revealed both fires were deliberately lit, and the station door had been doused with a highly flammable liquid.
Sergeant Glenn Ryan said he believed both arsons were linked and it was possible the attack on the recycling centre was a diversion to distract officers.
"We have had some issues with arson before but this is taking it to a whole new level," said Mr Ryan.
"We are a small bunch of guys working to serve a small community, so we are taking this as a personal attack.
"The arsonist made good work of the recycling centre, it's pretty much toast.
"So we are lucky they did a poor job of our place."
Mr Knight has served as an officer in Pahiatua for 12 years but said he had never come across such an attack on police property.
"We do interact with a lot of people and they aren't always happy with us," he said.
"But I've never seen anything like this.
"We strive to serve this community as best as we can, then this happens.
"So at the moment we're not so much scared as annoyed."
Since the arson attacks, police patrols in Pahiatua have been increased and officers are currently reviewing CCTV footage.
Detective Sergeant Shane Brown of the Tararua CIB said a vehicle was seen outside the recycling centre about 11.30pm on Saturday.
"We are interested in any suspicious activity in the area," said Mr Brown.
"Officers are continuing to make inquiries, and we want to speak to the driver and passengers of that vehicle."
Mr Ryan strongly encouraged Pahiatua residents to be vigilant and to come forward with any further information.
"If you see anyone dodgy or out of place, just let us know," he said.
"For us, it's a matter of when we catch this person, not if.
"This is a small place and someone in the community is bound to know something."
The penalty for deliberately lighting a fire on any property is a maximum of 14 years' imprisonment.
Anyone with information is asked to contact Shane Brown on (06) 213 9528. Alternatively, information can be provided anonymously via Crimestoppers on 0800 555 111.