Staff would be monitoring the volcano four to five hourly throughout the week to see what was happening before the level could be downgraded, Mr Jolly said.
"We like to take a longer view of things. Get as much information on the trend and activity ... it appears it was a minor eruption and ashing. It's just in an increased state of unrest at the moment."
There are monitoring systems and cameras on the island relaying information to GNS Science.
However, staff were currently restricting visits to the island because of the activity which had been presenting during the past two months, Mr Jolly said.
"We are limiting our exposure to the hazards and risks."
White Island Tours marketing manager Patrick O'Sullivan said increased alert level didn't impact the tour company.
"We already have procedures in place that we have been running for quite a while now.
"We haven't actually been to the island this weekend because of the weather."