Culture Secretary Tessa Jowell has said the anger felt by victims of the 7 July terror attacks towards the emergency response was "justified".
Tessa Jowell has spoken in support of the victims of the London bombings
The minister was speaking to the Sunday Telegraph ahead of an official government report into the experiences of survivors and victims' relatives.
Ms Jowell said excuses over failures would "cut no ice".
The report is expected to list shortcomings in the response to the London attacks which killed 52 people.
Ms Jowell, who is also the minister responsible for liaising with survivors and bereaved relatives, said: "I think that the anger that people feel is justified.
"People feel that after they have been an innocent victim of one of these atrocities they feel outraged by what has happened and I think that sometimes for some people insensitivity, unintended insensitivity, has made that worse.
"What is very clear to me is that if people feel they have not been properly helped within the first few hours, nothing is likely to change in their subsequent view."
The report, entitled Lessons Learned, will contain a number of recommendations to improve the response to any future attack.
According to the Sunday Telegraph, it will say communication failures and the lack of a central reception point compounded victims' trauma.
The report will recommend that reception centres are set up close to incidents in future.
As well as the lack of a central meeting place, there were complaints that the Metropolitan Police's casualty bureau phonelines were jammed with the volume of calls.
Families also complained that it took days to find relatives, while some were turned away from intensive care units because they did not have suitable ID.