McLAREN'S Fernando Alonso is said to be "conscious and speaking" after being airlifted to hospital following a heavy crash during the final day of the Formula One pre-season test in Barcelona.

The 33-year-old Spaniard was moved to the Circuit de Calalunya's medical facility by ambulance after the incident, and later transferred to hospital by helicopter.

Alonso's McLaren-Honda had left the track at Turn Three, and hit the wall side on.

McLaren said the two-time world champion was undergoing precautionary checks.

"Today at 12:35 CET, while testing at the Circuit de Catalunya (Barcelona), during the fourth and final day of the current test, Fernando Alonso's McLaren-Honda car left the track at Turn Three, causing the right-hand side of his car to strike the wall," a team statement said.

"Fernando was driven to the circuit's Medical Centre where the circuit's doctors gave him first aid.

"He was conscious and spoke with the doctors.

"However, as per usual procedure in such circumstances, he was then airlifted to hospital where he is undergoing precautionary checks.

"We will issue a further update in due course."

Prior to the accident, McLaren had endured a disappointing test session, with a faulty seal on the MGU-K - one of the energy recovery systems on the car - causing repeated problems.

The issue first surfaced on Thursday but a revised part fitted on Saturday did not resolve the problem and McLaren were forced to run with reduced power for the rest of the day.