More than 100,000 members have joined groups on Facebook expressing their grief over the deaths of 29 miners at the Pike River mine.

Thousands from all over the world expressed their sympathy with the families of the miners tonight on the site.

"Thoughts to all who have had the pleasure of loving these 29 men, New Zealand is behind you 100 per cent of the way through this tragic term," Ashlie Taylor wrote.

Many expressed also gratitude for the rescuers and Pike River chief executive Peter Whittall.

"RIP Miners and Heartfelt Sympathy to their families and all those involved with this tragedy. Peter Whittall you were amazing -- thank you for your calmness and honesty and thanks and blessings to all that were involved. God bless xx," Pam Hanretty wrote.

Chris Barr from Hamilton posted "A dark day for NZ. One explosion and 29 families ripped. My thoughts with all of you struggling through this tragedy. To the rescuers - Never for a second doubt yourselves. You did everything you could. This was out of your hands and your rescue attempts were 110 per cent."

Microblogging service Twitter was also abuzz with messages about the tragedy that has rocked New Zealand tonight.

While most expressed their grief and support for the families, some called for not giving up hope before there was evidence the miners were dead.

Others called for 10 minutes of silence on Twitter tomorrow at 11am in memory of the 29 lives lost or to put a yellow ribbon on their avatar to express their support.