A geologist believes re-entry into Pike River mine will be difficult and expensive.

The Government's announced today it's going ahead with plans to re-enter Pike River mine, opting to use the existing access tunnel.

The team hopes to be in by February.

The Minister responsible for re-entry Andrew Little acknowledges the costs will be higher than expected.

Geologist Dr Murray Cave told Larry Williams re-entering by February is a big ask.

"I suspect that to do it safely would take far more time than that."

Cave says Solid Energy assessed and rejected the chosen option.

LISTEN TO MURRAY CAVE AND TONY KOKSHOORN TALK WITH LARRY WILLIAMS ABOVE