The CEO of the Australian radio station responsible for the prank call to the hospital treating the Duchess of Cambridge has described the suspected suicide of the nurse who took the call as "tragic", but said he is satisfied the presenters have broken no laws.

Rhys Holleran, head of the Austereo network, which owns the radio station 2Day FM, said on Saturday the presenters could not have "reasonably foreseen" the events which unfolded.

"We are very confident that we haven't done anything illegal. We are satisfied that the procedures we have in place have been met," he said.

"Our main concern at this point in time is that what has happened is deeply tragic and we are incredibly saddened and we are incredibly affected by that."

Jacintha Saldanha, 46, a nurse at the private hospital treating the pregnant Duchess was found dead three days after taking the hoax call from the 2Day FM presenters.

It is understood Saldanha, a mother of two teenage children who had worked at the London hospital for four years, was the staff member who had answered a telephone call at 5.30am on Tuesday from the presenters posing as the Queen and the Prince of Wales. Believing them to be genuine, she had put the call through to a duty nurse, who then divulged medical details of the duchess's condition to the presenters.

Austereo CEO Rhys Holleran talks to the media during a press conference in Melbourne following the death of Jacintha Saldanha. Reuters

During a press conference in Melbourne, Holleran expressed "deep sorrow" at the events of the last 24 hours. He said had spoken to both of the presenters and said their show will remain off air until further notice out of respect. Both have been offered counselling.

"Our main concern is for the family (of the nurse). I don't think anyone could have reasonably foreseen this was going to be the result," he said.

"I spoke to both presenters early this morning and it's fair to say they're completely shattered.

"These people aren't machines, they're human beings. We're all affected by this."

Police stationed outside the King Edward VII hospital in London, where the Duchess of Cambridge was treated and where Jacintha Saldanha, the victim of the hoax phone call, had worked for more than four years. Photograph: Andy Rain/EPA

All advertising on 2Day FM has been suspended by its owner, Austereo, from Saturday afternoon.

"They want to keep their advertisers happy and they just pulled the advertising, only on 2DayFM 104.1 in Sydney, at least until Monday, just to keep advertisers happy right now," Austereo spokeswoman, Sandy Kay, told Fairfax Media.

"They're reassuring and speaking to advertisers but they've pulled them for the moment until they've cleared it all up with them."

Asked if the response was due fears of an avalanche of advertiser boycotts, Kaye told Fairfax Media: "I guess it probably is. They're not words that have been given to me, but I guess that's the understanding. The words that were given to me were 'in order to keep advertisers happy'."

Earlier on Saturday, Australian retailers had begun withdrawing advertising from the station. The supermarket giant, Coles, said in a statement on its Facebook page: "We understand Australians are clearly angry and upset by what appear to be tragic consequences of the 2Day FM UK hospital prank," Coles said on its Facebook page. "We have instructed 2Day FM to remove all Coles group advertising from the station."

Telecommunications heavyweight, Telstra, had also pulled its advertising before the suspension. A spokesman for Telstra told the Australian newspaper the telco had suspended "advertising on the station until an investigation into the issue has concluded".

Australians across the country expressed shock and disbelief at the tragic death of Jacintha Saldanha. A spokesman for the Australian prime minister, Julia Gillard said in a statement: ''This is a terrible tragedy. Our thoughts are with her family and friends at this time.''

The federal communications minister, Stephen Conroy, also described Saldanha's death as "dreadful and tragic".

"My thoughts and sympathies are with Ms Saldanha's family, friends and work colleagues at this time," he said in a statement.

Conroy confirmed that the independent broadcasting regulator, the Australian Communications and Media Authority (ACMA), had received complaints about the hoax call but said a decision about whether to investigate the prank call for possible breaches of the Commercial Radio Codes of Practice would be one for ACMA. ACMA has not currently launched an investigation. In a statement, it's chairman, Chris Chapman, said: "The ACMA does not propose to make any comments at this stage, but will be engaging with the licensee, Today [sic] FM Sydney, around the facts and issues surrounding the prank call." ''These events are a tragedy for all involved and I pass on my heartfelt condolences to the family of the deceased nurse in London,'' he said.

The Duchess of Cambridge, who was admitted to the hospital on Monday afternoon with acute morning sickness, hyperemesis gravidarum, was discharged on Thursday.

In a statement, St James's Palace said the duke and duchess were "deeply saddened" at the news of the nurse's death. "Their thoughts and prayers are with Jacintha Saldanha's family, friends and colleagues at this very sad time."

A St James's Palace spokesman added that the palace had "at no point" complained about the hoax incident. "On the contrary, we offered our full and heartfelt support to the nurses involved and hospital staff at all times".

But the call was deeply embarrassing for the hospital, which is the medical institution of choice for the royal family. It is understood that the hospital, which had described the hoax as deplorable, was not disciplining the nurses involved.

In a statement it said: "We can confirm the tragic death of a member of our nursing staff, Jacintha Saldanha. Jacintha has worked at the King Edward VII hospital for more than four years, She was an excellent nurse and well-respected and popular with all of her colleagues.

"We can confirm that Jacintha was recently the victim of a hoax call to the hospital. The hospital had been supporting her throughout this difficult time".

John Lofthouse, the hospital's chief executive, added: "Everyone is shocked by the loss of a much-loved and valued colleague". Lord Glenarthur, the hospital chairman, said: "This is a tragic event. Jacintha was a first-class nurse who cared diligently for hundreds of patients during her time with us. She will be greatly missed".

In a statement released through the Metropolitan Police, her family said: "We as a family are deeply saddened by the loss of our beloved Jacintha. We would ask that the media respect our privacy at this difficult time."

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