The Pike River families say manned re-entry of the Pike River drift is now inevitable.
Saturday night's preliminary election result suggests forming a Government is not possible without the support of parties which have committed to manned re-entry of Pike River.
New Zealand First leader Winston Peters has insisted on a re-entry into the mine, and the ultimate result of the election hinges on whether he goes with Labour and the Greens or National.
Sonya Rockhouse, who lost her son Ben in the disaster, said the result was great news.
"Thanks to NZ First and all of the other parties who have backed our cause we will now finally get truth and justice.
"We'll be making sure that any support Winston and other leaders need to get this done will be delivered."
Bernie Monk, who lost his son Michael in the mine, said the argument for manned recovery of the drift is now won.
"International experts have said it can be done, the people of New Zealand have seen how solid the drift is, now after seven long years we will finally have someone who will be critical to Government who is determined to do the right thing."
Anna Osborne, whose husband Milton was killed at Pike, said the argument for re-entry was now stronger than ever.
"When we got the cross-party commitment two months ago, we got a majority of MPs in support of getting our boys and the truth out of Pike.
"Tonight that majority has been strengthened."
The Government called the cross-party commitment a "hollow political stunt".
"This political commitment could not be done under New Zealand's workplace laws," Environment Minister Nick Smith said in August.