New Zealand First leader Winston Peters will meet with Pike families and supporters in Greymouth on Sunday as he continues to push for a re-entry into the mine.

"When the event happened the Prime Minister said they would go to the ends of the earth to find out what happened for these people. They have gone back on that," Peters told the Herald.

The Government is under renewed pressure from Pike River families to prevent state-owned coal miner Solid Energy from permanently sealing the mine on the South Island's West Coast and preventing re-entry to its drift.

The families have cited a report from international mining experts that said the mine could be safe to re-enter and that a new independent entity should be set up to oversee the project.

The mine has been closed since November 2010 after a gas explosion killed 29 workers.

Peters, who worked as a miner in Australia in the 1970s, said in December that he was willing to be one of the first back into the mine.

He also said the issue was a "bottom line" for NZ First and that Prime Minister Bill English "should get through his head right now".

In a media advisory for Peters' visit on Sunday, the Pike River families referenced that pledge, saying they greatly appreciate Peters "making re-entry to the mine drift a bottom line of any coalition deal". 

Asked today if that was the case, Peters said he didn't want to outline bottom lines to media.

"I'm not going to be getting into situations answering questions about what are bottom lines. What I am saying is that we, unlike any other political party, have made it very clear where we stand.

"We don't want a review, we want the miners to have the right - as their expert advice has told them - to go in as far as is possible."

Prime Minister Bill English has said the safety reforms that followed a royal commission into the 2010 disaster meant there were strict legal requirements about painting a one-storey house, let alone entering a potentially volatile mine.

Pike River was the "most dangerous workplace in New Zealand", he said, and approving a re-entry would go against the very health and safety laws passed by Parliament in response to the disaster.

Labour leader Andrew Little has promised the victims' families that a Labour Government would get an independent assessment of the mine and re-enter it if it was declared safe.

- NZ Herald