The Australian and New Zealand players' associations advised cricketers to stay away after the International Cricket Council decided Thursday to go ahead with the event, while England players will be asked if they want to travel to the South Asian country.
The ICC said it would appoint a special commission to ensure security at the September 11-28 biennial showpiece but it was not enough to quash concerns about the threat of Islamic militant attacks in Pakistan.
Australian Cricketers' Association (ACA) chief executive Paul Marsh said the body "continues to have serious concerns with our players touring Pakistan for the Champions Trophy and we are disappointed with the ICC's decision."
"We are seeking clarity on the purpose and role of the proposed task force, so we are unable to comment on it at this stage," Marsh said in a statement.
"Based on the independent information and advice received, we maintain that the risks are simply too great for the ACA to recommend that our players tour Pakistan at this time.
"We would expect Cricket Australia to adopt the same position," he said.
Cricket Australia, which makes the final decision on whether to take part in the tournament, was expected to make a statement later Friday.
In New Zealand, cricket players' association president Heath Mills said all of the players that he had spoken to were uncomfortable about travelling to Pakistan.
"We're very disappointed by the decision out of the ICC overnight," Mills told Radio New Zealand.
"There's been a strong view that we don't think Pakistan is a safe work place for the players and our position hasn't changed," Mills said.
"It's our strong recommendation to the players that they don't travel to Pakistan at this point in time."
Governing organisation New Zealand Cricket said it was talking to the players' association and its own board about safety concerns.
The England and Wales Cricket Board (ECB) meanwhile said it would consult key figures in the squad to see if they were still willing to make the trip and a decision could come as soon as Friday.
If the players opt not to go, the ECB would have to decide whether to send an under-strength team or pull out of the event entirely.
"Following the decision of the ICC, the ECB will be having further extensive discussions with a number of key stakeholders -- including England players and Team England -- to determine our decision," an ECB spokesman said.
"Once those discussions are concluded, the ECB will be in a position to make a clear decision."
ICC chief executive Haroon Lorgat said late Thursday that the prospect of pullouts was an "obvious concern", but urged players not to withdraw, saying the ICC would do all in its power to ensure their safety.
"It's not something that I treat lightly, but I think it's something that we can manage," Lorgat told reporters in the Sri Lankan capital Colombo.
But the ACA's Marsh said the ICC's decision was bad for the game.
"If it (the tournament) continues in Pakistan at this volatile time, unfortunately many of the world's best players won't participate, which is not a good outcome for cricket," he said.
Australia postponed a full tour of Pakistan in March-April this year due to the security situation. However, they agreed to reschedule the tour in two visits -- one-dayers in 2009 and Tests in 2010.
New Zealand cut short a tour of Pakistan in May 2002 after a bomb blast outside their hotel in the southern city of Karachi killed 19 people, including 14 French naval staff.
Pakistan is fighting Taliban and Al-Qaeda militants in its northwestern tribal regions bordering Afghanistan and has suffered a string of deadly suicide bomb attacks in the last year which have killed more than 1,000 people.