The earthquake resulted in multiple fatalities, with many trapped in collapsed buildings and massive damage to Christchurch city and surrounding areas.
A state of emergency has been declared in Canterbury.
The 111 system became overloaded shortly after the earthquake struck.
Calls made from Queenstown are ordinarily diverted automatically to Christchurch.
However, Queenstown police, fire and St John staff, along with the Arrowtown Fire Service advised anyone needing assistance to call them directly.
The system was functioning again just before 5.30pm, but Environment Southland warned it might still experience overloading, so people unable to connect were told to call the individual emergency service operators.
A police spokeswoman said two officers each from Queenstown and Wanaka and five from Central Otago were on stand-by to go to Christchurch.
The council was also on stand-by last night.
Mayor Vanessa van Uden, chief executive Debra Lawson and emergency management officer Brendan Winder met yesterday afternoon to determine what resources the council could provide.
Communications manager Meaghan Miller said although the council had not received a request for assistance, many council staff had offered to volunteer.
Yesterday afternoon, a Southland District Health Board spokesman said Queenstown's Lakes District Hospital was on stand-by to clear patients but was not cancelling elective surgery.
More than 1000 passengers and their ''meeters and greeters'' were estimated to have packed the Queenstown Airport terminal at the peak of flight disruptions caused by the earthquake.
Flights to Christchurch on both 68-seat Air New Zealand flights and one 177-seat Jetstar flight were cancelled.
Queenstown Airport Corporation chief executive Steve Sanderson said a further five flights were delayed and some flights were diverted to Queenstown from Christchurch.
''Christchurch folk are obviously stressed about people in Christchurch and getting home and we've been helping them the best we can,'' Mr Sanderson said.
The airport offered its firefighting personnel and resources to Christchurch International Airport, he said.
Help desks operated by the airport and Air NZ dealt with dozens of people in long queues.
Queenstown Airport customer services-terminal services manager Kay Mortimer said it had been ''very stressful'', with people concerned about what was happening in Canterbury, how to communicate with loved ones and looking for accommodation options in Queenstown.
Internet access became free for 15-minute slots so passengers could communicate online, while a ''strange and eerie silence'' came over the passengers watching live news updates on televisions in the terminal.
Airline staff contacted hotel operators to accommodate passengers who had to stay overnight in Queenstown, while passengers were also being updated every 15 minutes over the public address system.
All 10 rental vehicle companies operating in the Queenstown terminal were fully booked, following the demand for transport to Christchurch.
Queenstown Airport will open 90 minutes earlier today, at 5am, and the Jetstar check-in will open one hour earlier, at 5.30am, to cater for disrupted passengers.
