A couple were found dead outside their vehicle on New Year's Eve with their three young sons unharmed in the back seat.

Police discovered Heather Kelsey, 30, and Daniel Kelsey, 32, on the I-4 near DeLand, Florida, after investigating a report of a maroon SUV parked with its hazard lights flashing.

The boys aged from eight months to four years in age, were taken to Halifax Health Medical Center in Daytona Beach as a precaution.

Heather Kelsey, 30, and Daniel Kelsey, 32, were discovered by police on the I-4 near DeLand, Florida on New Year's Eve

Police arrived at the scene at 2:08am at mile marker 122 on the eastbound side of I-4 near DeLand

There were no immediate signs of foul play, Volusia County Sherrif Spokesman Andrew Gant told The Daytona Beach News Journal.

Medical examiners will conduct autopsies to ascertain the causes of their mysterious deaths.

Police arrived at the scene at 2:08am at mile marker 122 on the eastbound side of I-4 near DeLand, a report states.

They found Mr and Mrs Kelsey unconscious at the scene and they were pronounced dead a short time later.

Their sons aged eight months to four years were found unharmed in the back of their SUV

Police discovered the couple outside their vehicle around 2am on Saturday

The couple were found on the I-4 near DeLand, about thirty minutes from Daytona Beach

Daniel Kelsey's long-time friend Jerrell Jackson described the pain of coping with his death, which happened on Jackson's 32nd birthday.

Jackson told the News Journal that the couple's youngest son had recently started walking, and that the two were 'doing great' in their new city.

He said in a Facebook post: 'I can tell you Dan was a loving, devoted father (who) did anything for his kids,'