An international law expert believes there may have been an imminent threat to the Black Caps cricket team, which abandoned a tour in Pakistan minutes before the first match.

The eight-game tour was cancelled in its entirety last night, with the team citing unspecified security concerns.

"The Black Caps are abandoning their tour of Pakistan following a New Zealand government security alert," the New Zealand Cricket statement said. They did not comment any more specifically on the threat.

Waikato Univeristy Professor Alexander Gillespie said intelligence suggesting a threat would have likely come from New Zealand's security agencies, and possibly international partners in the Five Eyes network, rather than only from the team's security team on the ground in Pakistan.

He said the fact the Prime Minister Jacinda Ardern personally spoke to Pakistan's Prime Minister Imran Khan implies this was serious.

"This suggests to me that something was very specific and very targeted, and they had visibility of that threat," Gillespie said.

"They would not have done this lightly, so I think [the threat] would have almost been imminent to have made this decision, because this has ramifications on the sport, on the contract and on the countries' relationship."

He said there are also wider implications, which would have in part influenced Prime Minister Ardern's decision to personally speak with Prime Minister Khan.

"This will cast Pakistan in a very bad light, not just for this tour, but other countries will be thinking now 'is it safe to go?' so there's a reputational damage to the country at the same time."

Pakistan continues to claim there was no threat to the team.

The country's interior minister Sheikh Rasheed Ahmad told a news conference that Khan had tried to convince Ardern that the visitors were not at risk.

"[Khan] informed [Ardern] that the law and order situation is the best in our country, and we give a guarantee that there is no security problem here, there is no security threat."

But Dr Gillespie said Pakistan would be under pressure to deny the threat.

"It goes to the credibility of their country, to keep visitors safe," he said.

"We are connected to America, Britain, Australia and Canada, and each of these countries also has reach into these others parts of the world. This gives us huge amounts of material."

Ardern and the Sports Minister Grant Robertson both said they support New Zealand Cricket's decision, and said that "player safety is paramount".

Robertson said the threat "was credible and had to be taken seriously".

The Ministry of Foreign Affairs says it's in contact with the team as it plans its departure.

It a statement it said it provided "ongoing and consistent advice" that Pakistan is a high security threat country.

MFAT's Safe Travel website says there is a significant threat from terrorism in Pakistan, and incidents could be large and indiscriminate.

It said it continues to receive information that terrorist groups are planning attacks there, including against Western targets.

It lists sporting events as a potential target.

Few countries have toured Pakistan after the Sri Lanka team bus was fired at by 12 gunmen in 2009. Six members of the team were wounded, and eight people were killed - six policemen and two civilians.