Work is set to resume on an Auckland pipeline where a worker died in a methane explosion - even though it is not known where the gas came from.
Engineer Philomen Gulland, 48, was killed and six other people working on the water infrastructure project were injured following a blast at the Onehunga site on Saturday.
Network engineer Ian Winson, 47, remains in a seriously ill, but stable condition in Auckland Hospital on Monday. Watercare supervisor Harry Barnett, 56, and drainlayer Matthew Jamieson, 25, are in a stable condition.
Watercare says it was told on Monday morning it was safe to start pumping fresh air into the pipe.
The pipe is being examined and scoured out, before welding begins on Tuesday morning.
The water supply company believes the explosion was caused by methane, but does not know where the gas came from.
Frequent readings are being taken and work will be halted if any gas is detected. Workers should take about 12 hours to weld the pipe together, it says.