Mt Cook residents in the capital were warned earlier to expect some "pretty unpleasant smells" due to a wastewater overflow.

Wellington Water crews have been on site near the intersection of Tasman St and Hutchison Rd this afternoon to urgently manage the situation and protect the surrounding area.

"Unfortunately, we all know these overflows can create some pretty unpleasant smells, so if you can, please steer clear of the affected area", Wellington Water said on social media.

Wellington Water Customer Experience Customer Operations group manager Ian Dennis told the Herald crews have managed to successfully restore the network flow on Tasman St.

An investigation into the cause of the overflow was ongoing, he said.

The northbound lane of Tasman St remains closed and Dennis encouraged drivers to avoid the area if possible.

"We would like to thank members of the public for their patience."

Tasman St resident Ethan Morse said earlier this afternoon that he saw wastewater coming out of a sewer pipe.

"There was toilet paper and brown water ... at one point it did smell a bit pongy but it wasn't terrible."