Police said northbound-traffic should use Old Ferry Rd and southbound drivers are being diverted along Glenavy Tawai Rd.
Glenavy Volunteer Fire Brigade chief fire officer Bevin Joyce told Fairfax that it appeared a northbound vehicle had crossed the centre line before the crash.
Ten firefighters and two fire trucks attended the crash but they were stood down about 9.50am.
"The initial report was that a car had rolled and it was on fire," Joyce said.
"When we got there was a two car motor vehicle accident.
"There was just a lot of smoke and steam, two kilometres north of Glenavy.
"We secured the scene and searched for occupants."
Kurt Brown, who lives about 500m from the crash, told Fairfax that he was having breakfast when he heard a "noisy car" go past.
"We followed the fire brigade about 500m to 1km up the road, and it was just around the corner."
There was "nothing left" of one of the cars involved, he told Fairfax.
It was at 19 last year.
The holiday period this year started at 4pm Friday and ends 6am on January 4.
The other fatal crashes were:
• A female driver died in a three car pile-up on SH5 near Hamurana in Rotorua on Sunday.
• A person was killed Sunday on Pourerere Rd in central Hawke's Bay after a car rolled down a bank.
• Boney Biju died on his way home from his 21st birthday party when his car left the road and struck a tree near Hanmer Springs on Christmas Eve.
• Fijian national Lalita Devi was a passenger in a car that crashed on SH14 at Maungatapere on Saturday.
• On Friday. taxi driver Abdul Raheem Fahad Syed, 29, died in central Auckland when his car was hit by another.
