New Zealanders living on low ground were left confused after yesterday's earthquake, when the news media reported they needed to evacuate, but tsunami sirens remained silent.
Some Canterbury residents decided to flee inland straight away, while others waited for the sirens to sound.
But Civil Defence said the evacuation was a precaution and the sirens went on in a timely manner.
The earthquake struck just after midnight - but the tsunami sirens did not sound along the Canterbury coast until about 2am.
Mike and Janice were jolted awake by the earthquake just after midnight.
"We went outside and waited for the shaking to stop and when it did we went back to bed.
"It wasn't until our daughter called and told us about the sirens an hour or so later that we realised we had to get out," Mike said.
They waited up in the hills until the sirens stopped.
Jill Knight did not waste any time evacuating from her beach side home - she drove inland towards the airport.
"I read on Facebook that everyone on the east coast should evacuate.
"I kept listening and thought the alarms are not going but we left anyway."
Ms Knight said people were confused and knocking on doors to see what they should do.
Rachel Peach also did not wait for the sirens to evacuate with her family.
She said because she lived on the coast, the threat of a tsunami was the first thing that came to mind.
"The first thing we did was turn on Radio New Zealand and check the Civil Defence website, we had a heated discussion about the sirens and whether the sirens were going to come on, but they didn't.
"About 12.30am Radio New Zealand said the east coast should evacuate so we did."
Ms Peach made it to the top of the Port Hills an hour before the sirens started.
Canterbury Civil Defence emergency group controller Neville Riley said Civil Defence talked with scientists before making the decision to put the sirens on.
"We get the message from the Ministry of Civil Defence, which gives information on the likely height of the waves and where they will hit.
"The sirens went on less than two hours after the quake. It was well after midnight that we started to recieve messages and it was about an hour after that we made the decision to turn on the sirens," Mr Riley said.
Mr Riley said when the sirens did go on, people did the right thing and calmly left.
"The important thing was the evacuation took place, the waves were not as big as predicted, but we did the right thing and evacuated the foreshore."
Mr Knight said individual councils made the decisions, so not all sirens along the coast would have gone on at the same time.
Further south, Labour MP Clare Curran said she believed the civil defence in Dunedin was too slow to communicate and the earthquake illustrated the need for there to be more national co-ordination when it came to emergencies.
If a tsunami was on the way, every minute counted, she said.
"It took until 3 o'clock for Dunedin civil defence emergency to actually announce a local emergency and to explain which communities were affected and which communities should stay put."
"That was a long time for really worried people who were up in the middle of the night wondering if they should be going to higher ground or not," Ms Curran said.
Clarity needed on tsunami warnings - MPs
Following the quakes, MPs became a point of contact for members of the public who were confused about tsunami warnings, and were seeking advice on whether they should head to higher ground.
Labour MP for Wellington Central Grant Robertson bolted out of bed when the 7.5 magnitude quake hit, and said it was "probably the biggest shake I've experienced in the 20 odd years I've lived in Wellington".
But Mr Robertson said there seemed to be a lot of confusion once tsunami warnings were issued by Civil Defence.
It wasn't immediately clear what locations the alerts applied to, or what tsunami sirens meant in certain areas, he said.
"The first priority is to look after people who have been affected and there's been some dreadful things happen, particularly in the Marlborough region, but certainly as we review the situation I think it's really important we get a lot more consistency and clarity about what different warnings mean, and who they apply to."
National MP Chris Bishop lived in Petone and was just about to go to bed when the first quake hit.
"Just started off a slow rumble but by the mid point of it, it was sort of like you were surfing. The whole house was swaying. It was just quite frightening actually," he said.
Mr Bishop headed for higher ground as soon as he heard on the radio that people in low-lying areas were being urged to evacuate - but he said some people were confused by the tsunami sirens.
"No doubt the local civil defence guys will be doing a review of the Lower Hutt response and I'm sure that will be part of the conversation."
National MP Mark Mitchell took to Twitter last night to help provide advice to people throughout the country in regards to the tsunami threat.
For Rodney residents, Hibiscus/kowhai coasts there is no need to move to higher ground. Tsunami warning further south.— Mark Mitchell (@MarkMitchellMP) November 13, 2016
He liaised directly with Civil Defence headquarters, which he said did an excellent job.
"I think initially we were erring on the side of caution, which was the right thing to do, and until they were clear about what the threats were, it was better to send out information that prepared us for a worse case scenario," Mr Mitchell said.
Prime Minister John Key has not ruled out creating a ministerial role to oversee the quake recovery efforts.