Parts of the machine being used to put out the fire in the Pike River Mine have failed, causing it to be temporarily shut down.
The 'gag' unit had been operating continuously since Wednesday night, pumping carbon dioxide into the mine.
Twenty-nine men are dead since a series of four explosions that began on 19 November.
Hoses supplying water to the machine were found to be damaged on Saturday and were sent to Christchurch for copies to be made.
New hoses and fittings were transported back to the mine overnight.
Superintendent Gary Knowles says the shut down is not helpful, but experts say it's unlikely to hamper efforts to extinguish the fire.
He says the Polish designed, converted jet engine is a complex device and spare parts cannot be bought at a hardware store.
The machine is expected to resume operation later on Sunday.