The source of a foul smell shrouding central Auckland has been revealed.
Works to strengthen the Orakei Main Sewer is to blame, the City Rail Link says, as part of preparations to build a new train station on Albert St.
"No unacceptable levels of odour have been detected outside the site boundary," CRL spokeswoman Carol Greensmith told NZME - however it appears others in the area would not agree.
The stench has left some businesses unable to attract customers, despite the CRL's use of an odour suppressant.
Ms Greensmith told NZME the manhole was capped off whenever possible to keep the sewerage smell contained.
The sewer runs across the Victoria St and Albert St intersection - the same place a trench is being dug to install a pair of tunnels, linking the Britomart Transport Centre to Mt Eden.
No formal complaints have been made, despite the smell being present for three months - but it probably won't get any more pleasant as the weather heats up.