Today, he will receive a Group Bravery Citation from the Governor General in recognition of his actions that fateful day.

Not a day goes by where the Queanbeyan man doesn't think about that event, and he can still recall minute details from the tragic day. A day, he says, where he was "in the wrong place at the wrong time".

"I can still see the boat in the water and...I can still describe a couple of - unfortunately the children that were deceased - exactly what they were wearing, the colour of their shoes, pants, their tops. How their hair was done, if it was braided or in a bun," he said.

"I can vividly see and remember everything of that day."

In the early hours of December 15, 2010, the marine enforcement officer received an urgent knock on his cabin door.

They needed crew from the Australian Customs and Border Protection Service to help respond to reports of an asylum seeker vessel, known as SIEV 221, that had crashed at Rocky Point, Christmas Island.

In his seven years as a marine enforcement officer, Mr Marmont has become familiar with Christmas Island.

He's seen it plenty of times but that day, it was different.

The combination of the wind, rain and four to five metre swells made for trying and rough conditions. Even the officers' boat was struggling in the seas, let alone a primitive vessel with a broken motor and that lacked any kind of navigation equipment on board.

"As soon as we turned around the point of [Christmas] Island, you sort of knew it wasn't going to be a good day. Seeing the debris in the water and hearing, seeing and smelling what I did. It wasn't a nice experience," Mr Marmont said.

"Their boat - it was just disintegrated - it got thrown against the cliff face and rocks so it just broke up in the water. There was nothing left of it that you could picture that it was once a boat - other than just all the wood in the water, the people there and the smell of diesel in the water and air."

The team of six officers rescued 40 of the 90-odd people from that sunken vessel. It was a matter of literally plucking as many people out of the water as possible and running them back to the mother ship, Mr Marmont said.

"In the morning, it started out as a rescue mission and by about lunchtime it was a recovery mission, just looking for the deceased," he said.

"Our training is quite advance and our skills are at quite a high level. [But] you can never get taught to deal with that situation, you become a robot and you know what you have to do. Now that I think back about it, it was quite challenging."

Mr Marmont has never seen or heard from the people he helped to rescue. He only knows of one woman who he dragged from the waters. She had ingested a large amount of water and diesel and had to be medivacked from the Island.

The last he heard, she had survived but as for the rest of the survivors, he will probably never know.

Mr Marmont has been on plenty of rescue missions but never one with a loss of lives to this extent. The 45-year-old is humbled to receive an award for this particular job and previously received the Customs CEO Award and International Maritime Award for bravery.

He will be given the Group Bravery Citation award in an investiture ceremony this morning. Mr Marmont and his wife, Sonja are also a handful of people who have been choosen to dine with the governor general tonight.

"I speak for myself and I'm sure I can speak for everyone on the boat, we don't do the job for accolades," he said.

"I'll graciously accept the award because it feels nice to be recognised or thought about, that I did a good job.

"I suppose...I just happened to be picked. I was in the wrong place at the wrong time and got selected to go on the boat."

Mr Marmont said the event had a "profound effect" on his life. He carried the weight of what he witnessed and experienced with him for a long time and was eventually diagnosed with post-traumatic stress disorder.

"It took quite a number of counselling sessions to stop blaming myself. I blame myself for not pulling or dragging enough people in," he said.

"My wife knew within the first few weeks after I had returned that I wasn't the same person. In a way, I was scared to go back to work; I didn't want to hear that or see that or smell that, again.

"There's not a day that goes past, I don't think about it...but I can live with it now. I used to get really emotional, even when I read the papers, when there's been an asylum boat and I haven't been out there.

"I think now I appreciate life a lot more especially after seeing how quickly it can be taken away from you."