"Before I signed off on exploring those options further, I just wanted the families to know where we were at, and to have confidence in it.
"They seemed to, so I'll now sign off on that."
Little said a realistic target for re-entry was the end of the year.
"We think the end of December, and that's what we're working towards at the moment.
Little said the three options were quite similar, but had differences in how they organised a second exit point, and the order in which parts of the plan happened.
The planning would now move into more detailed work, sourcing equipment, and working out a detailed cost expectation.
He said both the Government and the families knew the recovery would be "complex".
Their experts said it was possible, but the risks had to be acknowledged and mitigated.
"It's a unique mine anyway, you've got this very long tunnel or drift, and it goes uphill," Little said.
"It is a coal mine, so it has all the usual hazards that go with methane and coal gas.
"And, of course, it's a mine that has already blown up.
"That's why we've got the expertise we have, and one of the operating principles we agreed to with the families, is safety first.
"They are very clear, they don't want another person injured or harmed in the re-entry exercise."
Last month police announced a new investigation into the Pike River Mine explosion was to be opened, five years after they closed their original one.
Assistant Commissioner Richard Chambers was in Greymouth in June to meet with the Pike River Recovery Agency and representatives of families of the 29 men killed during the methane blast eight years ago.
"The purpose was to discuss the police role and processes to come regarding planning for re-entry to the drift," he said at the time.
"Those discussions raised the option of a police member being seconded to work closely with the Pike River Recovery Agency, albeit remotely," Police said in a statement.
As well as Chambers visiting last week, Commissioner Mike Bush met with affected families in 2017 for the first time since police closed the case in 2013.
He said it was to express police support for the re-entry planning, as well as police commitment to completion of investigative steps if re-entry to the drift was achieved.
Pike River Mine is 46km northeast of Greymouth.
On November 19, 2010 a methane blast at the mine trapped and killed 29 workers inside, where they remain today.
Any new evidence found would be assessed to determine what, if any relevance it had on the original investigation which concluded in July 2013, police said.
