The family of the triplets killed in a Doha mall fire has been "overwhelmed by support and love", and is inviting the public to attend the toddlers' New Zealand memorial service.

The funeral and memorial for Willsher, Lillie and Jackson Weekes will be held at 1pm on Friday at St Paul's Cathedral on Molesworth St in Wellington.

The two-year-olds were killed in a fire that ripped through the Gympanzee childcare centre in Villagio Mall in the Qatar capital of Doha on Monday.

Their parents, Martin and Jane, will return from their Qatar home this week for the funeral.

Jane, who is from Wellington, returned to New Zealand from Qatar to give birth to the triplets because she suffered from the neonatal condition pre-eclampsia. The triplets were delivered by caesarean.

The family last visited New Zealand in February, spending time with family and friends, who have been left reeling by the deaths.

"It's surreal," family friend and Willsher's godfather Roger Beaumont told the Sunday Star-Times.

"For me, I don't think it will really hit home until I see Martin and Jane."

The young family had been to Beaumont's home, and he said it was a "fulltime job" keeping an eye on the lively triplets. "They were running around the garden," he said. "It was a fulltime job making sure we knew where they were."

His godson, known to his family as Winky, was always a lot of fun, he said. "He was a ball of energy, full of life."

He said Martin and Jane had decided to open the triplets' funeral to the public after being "overwhelmed by support and love" from around the world, and especially from New Zealand.

"In many cases these were people who they'd never met. Martin and Jane thought it was important to give the public the option, if they felt they had been touched by the tragedy, to share in their grief at a public memorial."

A private burial for family and close friends will follow the Wellington service.

In Qatar, the royal family last week announced a committee would investigate the fire, which killed 19 people. Five people, including the mall manager, assistant manager and assistant director of security, have been arrested.

- © Fairfax NZ News