Professor Ed Mitchell, a child health researcher at the University of Auckland, believed the change was probably due to an improvement in the message about bedsharing.
Of about 60 cases of SUDI recorded on average in New Zealand each year, just over half were due to sharing a bed with another person.
"Coroners have been talking about it in the media, the Maori and Pacific Island health groups have also been promoting avoidance of bedsharing and encouraging the use of the pepi pod," he said.
"It's enabling the message to get out to families, placing babies on their backs in their own cots, no smoking, encouraging mums to breast feed are all contributing to a change."
Prof Mitchell said despite the improvements being "very encouraging" the figures were still too high.
"Our best estimates are if every family was able to follow the pepe messages of their own bed, no smoking, back to sleep and breast feeding we think the SUDI numbers would drop to five to six per year."
GP and SUDI researcher Dr Christine McIntosh agreed that New Zealand needed to be aiming at least lowering to the Netherlands rate of SUDI death which would equate to 6 babies per year.
Dr McIntosh said there was a realisation that most of the infant deaths are preventable by babies sleeping on their backs and in their own bed.
She said the higher rates of SUDI among Maori was a reflection of the high rates of smoking in pregnant Maori women, which make a baby vulnerable because this renders a baby less responsive to low oxygen situations.
"I am a GP and I know that tremendous effort is put towards reducing smoking rates in New Zealand but still women smoke in pregnancy or are smoke exposed," she said.
"Therefore we have taken a different approach and intensified our efforts to ensure a safe sleep space for infants."
Leading Maori organisation for sudden infant death prevention, Whakawhetu, coordinated yesterday's first Safe Sleep Day that was adopted by more than 80 health providers and organisations in local communities across New Zealand.
National manager Kathrine Clarke said unintentional suffocation in the place where they sleep was the most common cause of death for infants under the age of 12 months.
The National Safe Sleep Day aims to turn this around.
Whakawhetu has worked closely with its partner organisations, TAHA and Change for Our Children, to bring this initiative to life and the organisations hope that Safe Sleep Day will become an annual event.
Ms Clarke said many babies would be saved if families followed the simple PEPE message.
The PEPE message
PLACE baby in his or her own baby bed, face clear of bedding, in the same room as a caregiver
ELIMINATE smoking in pregnancy, and protect baby with a smoke-free environment
POSITION baby flat on his or her back to sleep, face up
ENCOURAGE and support mum, so baby is breastfed
* In 2008: There were 134 post neonatal and 55 SUDI deaths. Last year there were 98 and 36 respectively.
* In 2010 there were 7.15 SUDI deaths per 1000 live births. This year the figure dropped to 4.66 - a 35 per cent decrease.
