Norway's prime minister announced an independent review into last week's massacre, as European anti-terror experts were to meet Thursday to examine ways of preventing a repeat of an Oslo-style massacre.

Amid growing criticism that it took officers too long to halt a killing spree by Anders Behring Breivik that left 76 dead, Prime Minister Jens Stoltenberg vowed that a commission of inquiry would get to the truth.

European Union experts were meanwhile set to talk to Norwegian counterparts in Brussels to discuss measures in hand to prevent another bloodbath, a diplomat told AFP, adding it would be an "exchange of information".

Police have already acknowledged they did not arrive on the island until an hour after being told about the shooting as there was no helicopter available.

But the controversy over the response time deepened when it was revealed at a police press conference that officers racing to the island had to requisition two civilian boats as their own vessel had engine problems.

Haavard Gaasbakk, the commander of the police team that detained Behring Breivik, told journalists that his men deserved praise.

"They were extremely solid and showed much courage right down the line," Gaasbakk told journalists.

Another officer did not say how long the initial delay was, but stressed that the team "gained 10 minutes" by using the civilian boats instead of their own troubled vessel.

Announcing the independent probe, Stoltenberg said the aim of the special "July 22" commission would be to "map out what functioned well and what functioned less well".

"It's important to understand all the aspects of these attacks, to draw lessons from what has happened," he told a press conference Wednesday.

Stoltenberg also announced that a national commemoration would be held on a date still to be decided, in honour of the dead from the shooting rampage on Utoeya island and the bombing of government offices on Friday.

The government would also make a financial contribution to the families of the bereaved, to cover funeral expenses, Stoltenberg added.

More embarrassment was earlier heaped on the police by the father of two teenagers on Utoeya who claimed he was told to "get your children to call us themselves" when he tried to alert police to the shooting.

After receiving an alarming call from his daughter, Geir Johnsen rang police but said he was met with a wall of incredulity.

"What happened is that I was absolutely not believed when I explained what my daughter on Utoeya had told me. I was told if that was the case, the children had only to call the police themselves. Even when I begged them to take me seriously," he told the local newspaper Fremover.

Freddy Lie, who lost a daughter on Utoeya, also told AFP that police had not believed him when he reported the shooting on the island.

Officers had told him that "it's in Oslo that it's all going on" when he reported the shooting after one of his daughters raised the alarm.

Stoltenberg said that lessons would be learnt from the tragedy, the deadliest event in Norway since World War II, after a period of national mourning.

"After the investigation and after we have in a way gone through the period in which we are now comforting those who have lost loved ones, there will be a time for going through all the experiences we have from the operation," he said.

Meanwhile a spokeswoman for the police union said the justice ministry had agreed to unblock funding to create 100 additional positions.

"These new resources are absolutely necessary," Gry Jorunn Holmen told AFP.

"There is enormous fatigue among the police in Oslo and the (Utoeya) area" where officers have interrupted holiday leave and worked round-the-clock since the attack, she underlined.

Norway's intelligence chief told AFP that Behring Breivik had most likely acted alone -- a fact that was making the investigation more difficult.

"He has probably, I think, no accomplices, so then is in full control. He's in control of the situation because only he can tell us what to do, and we don't have any sources," Janne Kristiansen told AFP. "He's totally evil."

Although authorities have said there was no evidence that Behring Breivik had links to other cells, a bomb scare at Oslo's main train station on Wednesday morning underlined the country's anxiety.

Breivik's lawyer Geir Lippestad told journalists on Tuesday that the case indicated his client was insane, adding that a medical evaluation would be carried out to establish his psychiatric condition.

Kristiansen rejected the suggestion.

"I have been a defence lawyer before and in my opinion this is clearly a sane person because he has been too focused for too long and he has been doing things so correctly," she told the BBC.