Stricken Test hopeful Phil Hughes is undergoing emergency surgery, having been rushed to hospital in a critical condition after being struck by a bouncer.

Paramedics performed mouth to mouth resuscitation on Hughes and treated him on the SCG boundary for around 40 minutes after he was taken from the field on a medicab.

He arrived at St Vincent’s Hospital in nearby Darlinghurst at 3.20pm (AEDT).

“He is in a critical condition and undergoing surgery,” said hospital spokesman David Faktor.

“He underwent a set of scans to assess the injury.”

Faktor confirmed Hughes was being treated for a head injury.

Hughes, 25, was hit by a delivery from NSW paceman Sean Abbott and fell flat on his face while batting for South Australia on the first day of their Sheffield Shield match.

The opener had scored a composed 63 off 161 balls and looked to be in good form to claim Michael Clarke’s vacant Test batting spot in next week’s first Test against India.

His injury prompted officials to call an early tea break with SA at 2-136 but play was then abandoned for the day.

Hughes’ mother and sister were in the stands at the game.

“Clearly the priority is Phil’s health and we want to keep his family fully informed,” a Cricket NSW spokesman said.

Hughes was accompanied to hospital by NSW team doctor John Orchard.

Hughes made his Test debut in 2009 and has played 26 Tests for Australia, compiling 1535 runs at an average of 32.66.