David Millane died earlier this week after a battle with cancer.
He was diagnosed shortly after a trip to New Zealand to attend the trial for his daughter's killer last year.
In a message posted to the Love Grace X social media channels, her family described the heartbreak of losing a husband, father and grandfather.
"Looking back on all of our memories together can be difficult.
"But the hardest ones are the new ones without you that just push us over the edge.
"Thank you for all your messages of condolence. We are heartbroken by the loss of David and he will be dearly missed.
"As you understand, now is a time for family. So we apologise if we don't respond to your message straight away."
The Love Grace X initiative collects handbags, toiletries and luxury items for domestic abuse charities.
It was started in honour of their daughter, who had a huge love for handbags.
Grace Millane made headlines in New Zealand and around the world when she went missing in December, 2018.
Her father David touched down in Auckland shortly after she was reported missing and made an emotional plea to the public for any information of her whereabouts.
Police at the time said they held grave fears for Grace.
Fighting back tears and at times struggling to speak, David Millane described his daughter as a lovely, outgoing, fun-loving and family-oriented daughter.
"Grace has never been out of contact for this long.
"She's usually in daily contact with her mother, myself, her two brothers ... and on social media."
The young woman, who was here on her OE, was last seen on CCTV footage in central Auckland on December 1 that year.
Her body would be found eight days later in the Waitakere Ranges, west of Auckland.
A man, aged 26 at the time, was convicted of her murder.
He was sentenced in February this year to life in prison with a minimum non-parole period of 17 years.
Grace and David Millane are survived by mother and wife Gillian and brothers and sons Declan and Michael and their families.
