The LaunchGood appeal is headed "Standing with victims and their families - United for Christchurch - New Zealand mosque shootings".
"Let us take this opportunity to show our solidarity with the victims and encourage love, tolerance, and unity," the appeal page says.
"All funds raised are going to be distributed to the families by NZIIC - New Zealand Islamic Information Centre.
"All proceeds will help with the immediate, short-term needs of the grieving families. No amount of money will bring back their loved ones, but we do hope to lessen their burden in some way."
The Givealittle appeal states that it is the official Victim Support fundraising page for victims of the Canterbury shootings.
"Dozens of families have been bereaved and many more injured by ... [Friday's] horrific shootings," the Givealittle page says.
"They deserve our help and support!" All donations received to this page will be used to provide support and resources for people affected by the Christchurch shootings and their family members."
Forty-nine people were killed in the shootings, described by Prime Minister Jacinda Ardern as a "terrorist act" and "one of New Zealand's darkest days".
Forty-one people died as a result of the shooting at Masjid Al Noor in Deans Ave near South Hagley Park west of the central city and seven at Linwood Masjid mosque in Linwood Ave in the east of the city. A further 48 people were injured.
A 28-year-old man is due to appear in court today charged with murder.
One of the gunmen livestreamed the shooting at Al Noor Mosque - which began at 1.40pm - in a chilling, 17-min video.
The main shooter was identified by Australian police as Brenton Tarrant — a white, 28-year-old Australian-born man, who uploaded to his Twitter account before the shooting a manifesto explaining his intentions.
Police Commissioner Mike Bush said three other people had been taken into custody — including one woman. One of those people was found armed at the scene but did not appear to have had anything to do with the killings.
Police were still "working to understand" what involvement the other two, who were also armed, had in the shootings.
Bush said officers had disarmed two improvised explosive devices found in a vehicle used by those believed to be behind the atrocity which has sent shockwaves through New Zealand and the Muslim community around the world.
• The crowding pages are at LaunchGood and Givealittle
