The bomb attacks in Sri Lanka on Sunday killed three out of four members of a Singapore-based British family, leaving the father as the sole survivor.

Lawyer Anita Nicholson, 42, their son Alex, 14, and daughter Annabel, 11, were killed by the blast while having breakfast at their table at the restaurant in Colombo's Shangri-La Hotel, Mr Ben Nicholson, 43, confirmed last night.

"Mercifully, all three of them died instantly and with no pain or suffering," he said in a statement.

Mr Nicholson is a partner in the Singapore office of Kennedys Legal Solutions. Mrs Nicholson worked as a managing counsel in the local office of international mining company Anglo American.

"Anita, Alex and Annabel leave behind a large extended family and many close and cherished friends who are now grieving this tragic loss. We shall all miss them dearly," added Mr Nicholson.

"Anita was a wonderful, perfect wife and a brilliant, loving and inspirational mother to our two wonderful children. The holiday we had just enjoyed was a testament to Anita's enjoyment of travel and providing a rich and colourful life for our family, and especially our children," he wrote.

"Alex and Annabel were the most amazing, intelligent, talented and thoughtful children and Anita and I were immensely proud of them both and looking forward to seeing them develop into adulthood. They shared with their mother the priceless ability to light up any room they entered and bring joy to the lives of all they came into contact with."

Mr Nicholson thanked the medical teams at Colombo's General Hospital for treating his wife and children with great dignity and him with kindness and sympathy.

Spokesmen for Kennedys Legal Solutions and Anglo American said they are in contact with Mr Nicholson, and are "supporting him in every way we can".

According to the Nicholsons' LinkedIn accounts, they relocated to Singapore from London in 2011.

British newspaper The Daily Telegraph reported that the family was holidaying in Sri Lanka and believed to have been there for about a week before the blasts on Sunday.

Most of the dead are Sri Lankans, but officials said more than 30 people from other countries have been killed by the explosions at eight sites, which include three churches.

Singapore's Foreign Ministry said on Sunday there had been no reports of Singaporean casualties so far.