Dec 9 (Reuters) - Britain's Unite union said on Tuesday some workers at Diageo's Belfast packaging site voted to reject the company's improved pay offer and resume a previously suspended eight-day strike action in December.

About 90 workers at Diageo's Belfast site are demanding a substantial pay increase to close the pay gap with employees at Diageo's site in Runcorn, England. 

However, a Diageo spokesperson said that the company expects no disruption to Guinness or Guinness 0.0 supplies over Christmas due to the union's renewed strike action plans.

(Reporting by Unnamalai L in Bengaluru; Editing by Alan Barona)