The standard three-year warranty has been extended from 60,000 miles to unlimited mileage for all models registered from November 1.
The paint warranty has also been extended from 12 months to 24. The six-year unlimited mileage corrosion warranty and three-year Europe-wide road assistance remain unchanged.
Trevor Houghton-Berry, general manager for MINI UK, said: 'This news is a reflection of our confidence in the Oxford-built MINI. British owners can rest assured that however many miles they rack up, MINI will take care of them.'
MINI parent company BMW announced last week it was to cut prices of replacement parts.