Driver under guard after fatal Vic crash

An unlicensed driver who crashed his car head-on into a minibus, killing an elderly woman and injuring eight people, has spent the night in a Melbourne hospital under police guard.

The crash happened at Rosebud, on the Mornington Peninsula south of Melbourne, on Wednesday morning.

The young driver suffered minor injuries but an 88-year-old woman died at the scene.

Police say the man's car was seen driving erratically before it hit the minibus carrying senior citizens on Wednesday morning at Rosebud shortly after they had set off on a day trip to Mornington beach.

Seven others on the bus were also injured, including a 91-year-old woman who was flown to Melbourne's The Alfred Hospital with critical injuries.

The bus was carrying two staff members from Ti Tree Lodge aged care facility and seven residents aged between 71 to 94.

Police believe the car driver from Coburg, who had a disqualified learner's permit, lost control of his car.

Police are investigating whether drugs or alcohol were a factor in the crash, and the driver has undergone a blood test.

They hope to interview the driver on Thursday.