Some reports say 12 buses were also involved, and so many cars were involved that by Tuesday evening, police had still not released an exact count.
Osman al-Tamimi of the Abu Dhabi police department said: "More than 300 people were injured in the accident, of which 6 were critical, while another 39 were serious, but stable."
Al-Tamimi said the rest of the injured sustained minor injuries and were taken to Abu Dhabi's two main hospitals, Al Rahba and Al Mafraq.
The official added that more than a dozen cars burst into flames during the accident, turning the highway between the United Arab Emirates' two main cities into an inferno.
Another police spokesman said: "Everyone was speeding, and after the first crash happened, people just started hitting each other."
Investigating authorities have cordoned off the site and both Dubai and Abu Dhabi police were enquiring into the incident, until late in the evening.