THE death-driving charges against Tasmania's Director of Public Prosecutions, Tim Ellis, began hearings in Hobart yesterday.

Mr Ellis, 58, had pleaded not guilty to causing death by negligent driving from a three-vehicle crash on the Midland Highway a year ago, which claimed the life of 27-year-old West Launceston woman Natalia Pearn.

Crown prosecutor John Pickering, SC, told magistrate Chris Webster he would call two witnesses who saw Mr Ellis's Mercedes move on to the wrong side of the road for up to one kilometre at Spring Hill.

Mr Pickering said the witnesses would describe the driving as ``immaculate'', and that it would be alleged that Mr Ellis's driving was ``conscious and voluntary''.

Defence lawyer Michael O'Farrell said the allegations by the prosecution were ``extraordinary'' because there was no evidence of Mr Ellis applying brakes or taking evasive steps before the crash.

Mr Ellis's wife Anita Smith was called as the first witness and described her husband as ``a very safe driver''.

Breaking down in the stand, Ms Smith recalled the moment of the crash as ``the loudest noise I've ever heard in my life''.

``It was like a hole in the earth had opened up and we had fallen through it,'' Ms Smith told the court.

Ms Smith said she had her head down and was sending a message to a friend during the moments leading up to the crash and was not aware the car was on the wrong side of the road.

``I presumed I was dead,'' she said.

Ms Smith said when the pair reached Campbell Town on the day of the crash Mr Ellis had said he ``was sick of driving''.

In a police interview two days after the crash Mr Ellis told police from his hospital bed he remembered one ``fierce impact'' and the car coming to a halt.

``I could feel my legs break,'' Mr Ellis told police.

``I can't remember seeing anything in front of me,'' he said.

The police read Mr Ellis comments from two witnesses describing his car as being on the wrong side of the road and Mr Ellis replied: ``That's news to me.

``Unless I'm not fully conscious or I've somehow got confused,'' Mr Ellis said.

``I wasn't feeling drowsy,'' he said.

Mr Ellis told police it was possible he had fallen asleep or experienced the effects of sleep apnoea.

``I do have a history of it but I thought I'd overcome it,'' he said.

Mr Ellis told police in the interview he was ``awfully sorry the girl was dead''. 

A video re-enacting the driving alleged of Mr Ellis was played to court.

Crash investigator Senior Constable Kelly Cordwell drove a Mercedes the same model as Mr Ellis's at the scene of the crash.

Senior Constable Cordwell took her hands off the steering wheel to examine what the car would do at the spot where it was alleged Mr Ellis was on the wrong side of the road.

The video showed the Mercedes veering back to the left-hand side of the road.

She told the court: ``To stay in the wrong lane, steering was required.''

Senior Constable Cordwell said Ms Pearn was wearing her seatbelt.

Alcohol was not a factor.

The hearing continues today and is expected to run until Thursday.