An Australian researcher who blasted Santa Claus as a bad role model for children defended himself Friday as a believer of the man in red and said his study was a festive "spoof".

Monash University's Nathan Grills said his study claiming Santa Claus promoted obesity, drink-driving, speeding and an unhealthy lifestyle had been written in his spare time for a bit of "comic relief".

"Most of my 'Santa - A public health pariah?' article was meant to be tongue-in-cheek... It's a Christmas spoof," Grills told Australian Associated Press.

"I hoped to spread a bit of Christmas cheer, but with a tinge of seriousness to provoke a bit of healthy Christmas dinner table conversation."

Instead, Grills said his study, which was published in the British Medical Journal, had attracted a barrage of criticism from all over the world accusing him of being a humbug.

"To clarify, I am not a Santa researcher. The article was written in my spare time for a bit of comic relief," said Grills, who declared himself an avid "Santa believer and lover".

Epidemiologically, Grills had claimed there was a correlation between countries that venerate Santa Claus and those with high levels of childhood obesity.

Instead of wolfing down mince pies and brandy and idling in his sleigh, Grills suggested Santa should go on diet and swap his reindeer for walking, jogging or cycling to deliver his presents.

His respect for road rules and safety when undertaking extreme sports such as roof surfing and chimney-jumping also left a lot to be desired, the study said.

It also bemoaned the potential infectiousness of Santa impersonators, saying if they sneezed or coughed around 10 times a day, all the children who sat on their laps could end up with swine flu.