Emergency law and an overnight curfew have been imposed in Sri Lanka as authorities search for those behind suicide the bomb attacks that has killed at least 310 people.
A police spokesman says the number of people arrested has risen to 40.
They are mainly Sri Lankans, although police are investigating whether foreigners were involved in the attacks, which were carried out by seven suicide bombers.
Government agency Safe Travel says there is an ongoing threat of violence in the country, and the threat level has been raised from green to yellow.
House of Travel's Brent Thomas told Heather du Plessis-Allan that they are expecting Kiwis to make inquiries within the coming days about their future travel plans.
He believes that most New Zealanders will wait and see.
"I think what's happened in these situations is that people take a moment and consider them. They have paid a significant amount of money to go on these holidays, and insurance won't necessarily cover those sort of expenses."
He says that as long as there are no further instances, most people will still travel, but he expects a six week period where holidays won't be booked.
The Australian Government has taken a hard-line urged travellers to consider changing their plans, saying "there are serious and potentially life threatening risks making the destination unsafe for tourism".
Thomas says that it's a situation where the New Zealand Government is waiting to see whether this is an isolated incident.
"We will have to wait and see what the Government does."
He says it will be upgraded if there is another incident.