The company operates a fleet of 800 cars, previously supplied by Toyota, Nissan and Rover. It signed with Vauxhall following a tender process that involved nine motor manufacturers.
Royal Liver's UK direct retail operations director Colin Nugent said: 'We evaluated the safety, reliability and accident records of a number of cars and were most impressed with Vauxhall's record.
'Another factor was the fact that Vauxhall builds cars at Ellesmere Port nearby and we wanted to work together and support a local employer.
'The fact that the new Astra is soon to arrive was also important and we will be running a number of existing model 1.6i Club versions before the new car is launched in a few months' time.'
Royal Liver will source about 350 Astras and 400 Vectras and will also consider taking a number of Saab models for its regional managers and supervisors.
The vehicles will be supplied on a contract purchase arrangement with Interleasing and will be operated on three year/ 40,000 mile and three year/ 60,000 mile contracts.