The Emergency Manager for Irish aid agency Trócaire said the security situation in Pakistan is preventing aid from getting to people who need it.
Maurice McQuillan said that political and military agendas in Pakistan were being pursued in the middle of a humanitarian crisis.
The Taliban has threatened to attack foreign aid workers who are providing relief to the millions of people affected by the monsoon floods.
There have also been several sectarian bomb attacks in Pakistan in the past week.
Mr McQuillan said the crisis is the worst he has witnessed as an aid worker and believes it will 'take years to rebuild Pakistan'.
Interior Minister Rehman Malik said that pro-Taliban militants are trying to create a sectarian rift.
He said: 'Sectarianism that has been there for 62 years (since the creation of Pakistan), they stoked it again.'
The Pakistani Taliban claimed responsibility for bomb attacks that killed 33 people in Lahore on Wednesday and 65 people in on Friday.
The attacks ended a lull after the devastating floods, which have affected 20m people.
Mr McQuillan said yesterday that women and children are in danger of being separated from their families because of the flooding.
He said: 'We're really worried about the safety and welfare of vulnerable women and children.
'Many families have become separated in the mass displacement of people caused by the floods.
'Many children are travelling alone and are at high risk of malnutrition and hunger, infection and disease, abduction or kidnapping, exploitation or abuse.'
