The world's largest package delivery company said in a press release that it expects a 6 percent increase in delivery volume during "peak week," which is the seven-day stretch leading up to Christmas. UPS expects to deliver more than 120 million packages around the world during this period, compared with 113 million delivered during the same period last year.

The company said that the growth of e-commerce is expected to condense the holiday's highest-volume shipping period to the last two weeks before Christmas, compared with the traditional highest-volume season spanning from Thanksgiving to Christmas.

UPS expects volume in half of the last 10 days before Christmas will approach or exceed 25 million packages a day. That compares with average daily volume of about 15 million. The peak shipping day is expected to be Dec. 22, with delivery volume approaching 26 million, while the peak air day should be Dec. 23, with more than 6 million air packages delivered.

The 55,000 UPS seasonal hires will work throughout the country as loaders and unloaders, and assist drivers.

"Early indications point to a solid holiday shopping and shipping season," UPS Chief Marketing Officer Alan Gershenhorn said in a statement.