"We are making a difference ... I'm right up there and I'm on top of it," he said.
"I have six courts to sit in, three major hospitals - that's doctors ringing me all the time. The workload is very high."
Dr Bain often works into the wee hours and often talks with parties after hours.
People needed to understand there was a lot involved before an inquest, he said.
"Okay, we get a post mortem, sometimes that can take months to come back. We get ESR to do blood - that can take a long time. I may need to get further information and then [if] there is a prosecution, the act says I have to stand aside until that is completed.
"Then you have to give people notice and sometimes that doesn't suit and then you have to get experts in. Then the evidence has to be prepared. Then I have to consider it."
He said it was frustrating when recommendations he made were not followed through.
"I'm at my wits' end of coroner's recommendations falling on deaf ears."
One of his biggest bugbears is the preventable deaths of between 55 and 60 babies each year as a result of bed sharing.
"These are totally preventable deaths. If they followed the recommendations I made, I reckon they could cut baby deaths down [to the] infinitesimal. We would be saving many, many babies."
However, some changes had occurred as a result of recommendations after inquests, he said.
Three one-lane bridges at Benneydale on which motorists had been killed were replaced by two-lane bridges several months after recommendations he made following inquests into the deaths. He warned Transit New Zealand there would be further deaths if something wasn't done.
Initially Transit said it didn't have the money to replace the bridges. Dr Bain told Transit it was in his view guilty of manslaughter if nothing was done and more deaths occurred.
"Once that got through to the board, within about three months there were two-lane bridges right the way through ... that has saved lives."
There are other successes too, including flashing lights being erected at the intersection of State Highways 1 and 27.
"There has not been one death there since," Dr Bain said.
There is also sadness over recommendations he made which have not been acted upon.
He believes if his recommendations after a Taupo jetski accident which resulted in the death of Genevieve Lewis had been followed, Rotorua teenager Bishop Thompson, who died after a jetski accident on Lake Okareka, would be alive today.
"I don't think that death would have occurred."