Tributes continued to pour in yesterday for the 2000 Sydney Olympic Games sprinter, who died in a car crash south-east of Darwin in the early hours of Tuesday morning.

Speaking for the first time, Natalie Sainsbury last night said the 31-year-old's family was the most important part of his life.

''Dan was a loving father of three beautiful children,'' Ms Sainsbury said.

''He always wanted a big family, it was the most important thing to him. He was currently studying at university and loved his career in the Attorney-General's Department.

''He was the happiest he had ever been with me, his kids and career.

''It is the most stable he had ever been and he had no regrets in leaving sport and living his new life with us.''

Batman was in the Northern Territory on annual leave visiting his two oldest children, 10-year-old Destiny and Jack, 8, from his first marriage, to Olympic hockey gold medallist Nova Peris.

Batman and Sainsbury had been together since October, 2010 and had their first child together late last year, eight-month-old Liberty.

He briefly attempted a comeback for next month's London Olympics.

However, he decided to focus on his career instead.

He was working with the Department of Families, Housing, Community Services and Indigenous Affairs' Stolen Generation Working Partnership at the Attorney-General's office, where he had been for the past two years.

''Daniel applied the commitment, dedication and determination he learnt from his sporting life to his everyday work,'' a spokesperson said.

''His loss will be deeply felt by all who knew and worked with him.''

Batman was also studying a Bachelor of Management at the University of Canberra.

Born in Melbourne and raised in Sydney, Batman is in the top 10 fastest Australian men over the 100 metres, 200 metres and 400 metres, with his best performance a sixth place in the 400 metres at the 2003 world indoor championships.

He was also the Australian national 200 metres champion in 2005 and 2008.

A schoolboys rugby union star, Batman trained for six months with the ACT Brumbies in the 2001-02 off-season before ending his premature retirement from the track with spectacular results.

Former Brumbies captain Stirling Mortlock expressed his shock at Batman's death.

''Thoughts & prayers go to Daniel Batman's family … I still remember the days when Bats was @BrumbiesRugby & returned to aths & #Dominated,'' Mortlock tweeted.

The news of Batman's death spread around the world, with Trinidad and Tobago's ex-world champion Ato Bolden joining Olympic-bound Canberra athletes Melissa Breen and Lauren Boden in using social media to give their condolences.

Former Australian sprint queen Melinda Gainsford-Taylor was in the 2000 national team with Batman and described the impact it had on the tight-knit athletics community.

''It's really hit the athletics fraternity hard,'' Gainsford-Taylor said, adding he was a talented athlete.

The crash, on the Arnhem Highway, was believed to have happened just after midnight on Tuesday, although police were contacted by a passing motorist at about 7am.

Detective Acting Senior Sergeant John Worrall from the Major Crash Investigation Section said it was believed speed and alcohol might have been contributing factors in the crash.

Batman's funeral arrangements have not been announced.