"It was already too late": Distraught parents speak out after son dies in baby swing.

Heartbroken parents Jeremy Rainsford and Emma Granger have shared a devastating warning to other parents after the sudden death of their three-month-old son, Kayden, on Sunday.

Kayden died after he was left for just 60 seconds in a baby swing.

Father Jeremy Rainsford told 7 News he had fed and burped his young son before placing him in the swing so he could quickly visit the toilet.

When he returned just one minute later, it was already too late.

Jeremy performed CPR on his three-month-old son.

"It broke me," the Perth father told 7 News.

"It was upsetting, having to perform CPR on my little son."

Emma said they sat with their little boy and "just talked to him".

"[We] told him that everybody loved him and that we loved him," she said.

"I told him not to leave me...but he was too far gone."

The couple isn't blaming the swing for Kayden's death - they believe he died in a freak accident after choking on his own vomit - but they are issuing a warning to all parents about using them.

"Don’t leave your children unsupervised in those swings," Emma said.

"They say you can and they’re designed to leave them to sleep in them."

The exact cause of Kayden's death will be investigated by the coroner.

A friend of the family has set up a GoFundMe page to help the family prepare for Kayden's funeral next week.