Normal enemal paint will hold for a while but will be easily chipped. If possible take the tap off, dismantle and thoroughly degrease. Tape up the parts you don't want to paint. Use a spray can of that porcelain enamel the store sells for touching up fridges, stoves etc. it dries pretty quick and can be recoated in 2 hours. Put 4 thin coats on and this should last for years.
Don't forget to use some 'plumber's grease' on the spindle when re-assembling the tap and replace the washer while you're at it..