UPS and TNT Express do not now expect their multi-billion euro merger, announced in March, to be completed until early 2013.
The operators had originally hoped to seal a deal in the first half of the year, but involvement from the European Commission as regulator scuppered this timetable.
Last month the European Commission temporarily suspended the takeover to allow regulators more time to gather information, a process that is ongoing.
Despite this UPS and TNT had still expected to complete the deal in 2012, but this deadline will now to be met.
The merger of UPS and TNT Express will create a €45bn (£35.7bn) company with true global reach.
