After about an hour they have been moved some 2km down the road and are still in lockdown.
They had been told one shooter had been shot dead and an unknown number was believed to be still on the loose.
Ben Northrop of Wellington had just turned up in Las Vegas for a business meeting.
"We literally drove down the strip, never been here before and it all teed off in front of us.
"The first sign of trouble was people running towards them and police heading away.
"There were guys saying there were bullets had just gone over their heads. We talked to a woman and the woman next to her had been shot in the head."
He said he was "just down the road from the Mandalay" and could see people covered in blood who had fled from the shooting.
Northrop and business partner Callum Macleod were in Las Vegas for a conference.
Northrop said today he can't get over the dramatic change in scene in Las Vegas from last night - when they were confronted with injured and bloodied concert-goers - to people now back in the pool and drinking beers at the hotels.
Northrop said it was absolute bedlam last night but now it was "surreal".
"It's been pretty surreal actually, the difference today was that we got into the hotel last night finally about 3.30am after sneaking our way around past gun battles and large amounts of police and soldiers and the like, and then when we came out this morning about 7am the contrast couldn't have been any greater.
"When we got in we had to park miles away ... and the lobby was just full of guards and scene guards and everyting was incredibly eerie walking through hotels of casinos that were empty. We got up this morning and the place is pumping, people are drinking, the casino's full, there's people in the pull. It's weird. I'm just in shock, looking at all these people."
Northrop said they had just landed and were heading to their hotel, the Bellagio when they came across the horrific scenes.
"We drove into it and was complete madness ... we bumped into quite a few people along the way with some very terrifiying stories an covered in blood."
Northrop said he spoke to a woman who had been serving drinks at the concert and the woman beside her got shot in the head.
"So she was covered in blood and completely freaking out."
He said they continued to bump into people who were either covered in blood from being shot or from helping those that were injured.
"We didn't see the actual shooting but the aftermath was pretty traumatic ... there was panic on the streets and were told there were multiple shooters so we didn't know which way to go. You were coming across people covered in blood. It was all very strange. Our first day in Vegas, wicked. Up all night for all the wrong reasons."
Northrop said they were due to launch their new digital insurance company, Vallum, at a conference at Ceaser's Palace today before leaving on Friday.
However, after hearing news that Tom Petty had died and another shooting had taken place at Southern California University he was unsure how much work would get done.
Another witness, named Zac, told Fox News he was right in front of the concert stage at Mandalay Bay when "all of a sudden there were these 'pops' like from a firework - 1, 2, 3 going off."
He said the firing was coming from the top of the Mandalay Bay.
"My sister saw in plain sight a girl get shot in the head."
He bunkered down, telling the people next to him to "Calm down, calm down" and holding the hand of a girl next to him. The gunshots continued and the crowd was told to run, he said.
An Australian tourist named Danny told CNN he was in the Mandalay Bay and described chaos at the scene as officers ran into the building's lifts.
"They were going up, they were coming down, they were going this way, that way. We were told to get out, told to get in - one shooter's up there still, we were told by police, and one's roaming around."
"A lot of people heard gunshots - the initial gunshots were apparently machine gun fire."
He and a group of around 14 people had stayed together for safety but were unsure where to run to, Danny said.
SWAT officers were everywhere, and at one point had told the group to put their hands up. Police appeared confused about the shooter's location or whether there were multiple shooters, he said.
Asked what ran through his head, he said: "I'm from Australia - we don't cop this sort of stuff in Australia that much. But you just try and keep people safe."
A spokesman for New Zealand's Ministry of Foreign Affairs and Trade said there were 44 New Zealanders registered on SafeTravel as being in Las Vegas and 2157 in the USA.
"The New Zealand Consulate-General is in contact with the local authorities. There are no indications at this stage that any New Zealanders have been caught up in the incident," he said.
"Any New Zealanders in the vicinity are advised to stay indoors, follow any instructions issued by the local authorities and let their family in New Zealand know they're okay.
"New Zealanders who require consular assistance are advised to contact the New Zealand Consulate-General in Los Angeles: +1 310 566 6555."
