Mystery surrounds a suspicious car fire on State Highway 29 last night.

Early morning commuters near Maungatapu have been passing the remains of the vehicle that caught fire shortly after 10pm.

Emergency services described last night's car fire on SH29 as "suspicious". Photos & Video: Cameron Avery.

The engine bay fire was attended by Mount Maunganui volunteer fire fighters.

However, Fire Service's Northern Communications shift manager Dallas Ramsay has no other information to pass on today.

Western Bay of Plenty road policing manager Senior Sergeant says: 'We were called to a suspicious car fire at around 10:10pm.

'The fire was in the undercarriage of a silver Sedan and the informant told us it was on the side of the road and didn't have its hazards lights on.”