They've had serial killers, surgery disasters and Chris Warner discovering his son's penis on a family iPad.

But one viewer says the image of plastic surgeon Drew McCaskill slipping over in a flood of raw sewage has "scarred me for life".

The moment came during last night's episode when Drew, played by Ben Barrington, and his partner Harper Whitley, Ria Vandervis, disovered water flowing down their hallway.

As Harper looked on, Drew ventured down the hallway to see what it was, only to yell, "It's a poo-nami!" at her.

Drew McCaskill, played by Ben Barrington, during last night's episode of Shortland Street.

Then, for several agonising moments, Drew floundered around as raw sewage - including fecal matter - flowed down the hallway.

The scene ended with Drew meekly saying: "Help me."

The moment has left viewers wondering what they'd just seen, with one asking: "What even is Shortland Street now?"

Others expressed disgust at the show airing a scene involving raw sewage at a time when they were eating dinner.

Bahahaha, whoever it was that designed those there turds needs a dam pay rise....best giggle in a while 😂😂😂💩💩💩#poonami #ShortlandStreet 👍🏼

— Meg's (@megskelly75) April 30, 2018

#ShortlandStreet ITS A POONAMI HAHAHHA OMG GROSS

— natalia (@QueenPfan) April 30, 2018

The "poo-nami" scene comes just over a year after Shortland Street sparked international headlines with a scene involving Chris Warner declaring, "Please tell me that is not your penis!" after finding a nude photo of his son on an iPad.

The line was named the Quote of the Year for 2017.