“Motorists should factor extra time in their journey when using the diversion.”
A Fire and Emergency NZ spokeswoman said seven trucks were called to a crash just after 2am.
Two fire trucks and one tanker were still at the scene, as of 6am.
The spokeswoman directed all other queries to police.
NZ Transport Agency said SH5 was closed at the intersection of SH30.
Southbound light vehicles to detour via SH30, Bryce Rd, Waikaukau Rd, Rehi Rd, Corbett Rd and Tumunui Rd, reverse for northbound travellers.
Odour ‘very noticeable’
A Bay of Plenty Regional Council spokeswoman said the tanker’s fuel tank was punctured and a significant amount of diesel had been released into a drain which led to the Kauaka Stream.
She said the odour was “very noticeable.”
“Staff have now carried out an investigation downstream of the incident.
“A sheen was observed on the Puarenga Stream, 3 -4km downstream of the site in the Waipa Mill Road area,” the spokeswoman said.
“No sheen was observed on the Puarenga Stream, near the Whakarewarewa area. There is no diesel being discharged to water.”
The spokeswoman said absorbent material had been spread around the site of the crash to reduce the risk of further diesel spreading on land.
“A road sweeper truck will later clean this up. A sucker truck is also on route to suck up any remaining discharge to land.
“Fire and Emergency New Zealand are still overseeing the site, and our focus is on reducing impact to the environment.
“Our staff will remain on site until we are no longer needed.”
More to come.