(Adds comment from Amazon Italia)
ROME, Oct 4 (Reuters) - The head of one of Poste Italiane's parcel units said on Wednesday a month-long strike by workers at some contractors was crippling parcel deliveries and hurting restructuring plans.
Parcel deliveries are seen as a valuable growth area for the Italian post office. Its SDA Express Courier unit is one of the companies that delivers parcels in Italy for e-commerce giant Amazon.
"Losing suddenly 50 percent of our volumes in nearly a month is devastating," SDA CEO Paolo Rangoni told a parliamentary committee. "The strike is affecting SDA's restructuring ... and even Poste's reputation is suffering."
Rangoni said Milan was the city most affected.
Workers in Italy's business capital went on strike after losing their jobs at a firm that used to be an SDA contractor and were then re-hired on worse terms by another company that also handles parcels for SDA.
"While we wait for the situation at SDA to return to normality, we have redirected our parcels to other couriers to avoid delays for our customers in Italy," Elena Cottini, head of communications for Amazon Italia operations, told Reuters.
In Britain, Royal Mail workers have voted to strike in a dispute over changes to the pension scheme, threatening delays to the Christmas post.
Poste Italiane has been hurt by the substitution of traditional mail with digital communications and is aiming to offset the fall in letters with growth in its parcel business.
State-controlled Poste has a target of bringing its combined mail and parcel division to break even by 2019 as a part of a turnaround launched in 2015 when it was partly privatised. (Reporting by Massimiliano Di Giorgio; Writing by Francesca Landini; Editing by Keith Weir and Edmund Blair)