The Department of Labour says it is satisfied everything possible is being done to keep contractors safe as work resumes at the site of a fatal gas explosion in Auckland.
A 48-year-old Canadian engineer was killed and six people injured during work to connect two parts of a water mains pipe in Onehunga on Saturday.
Three of the men injured in the explosion are in a stable condition at Auckland Hospital. The most seriously injured remains in intensive care.
Any work in enclosed spaces underground carries with it the risks associated with methane gas. But the Department of Labour says all the right safety precautions are being taken by Watercare and contractors as they return to work.
Watercare says preparatory work has been carried out on Tuesday ahead of welding work needed to complete the job and it is monitoring gas levels.
The department is investigating the explosion and says this could take up to six months.
Resumption of work questioned
An engineering geologist at Canterbury University has questioned work is resuming while the source of the explosion remains a mystery.
David Bell says he would be trying to find the source before beginning work and risking a second explosion.
He believes it could be coming from a pipeline or a natural underground source.