"It's not good enough. I'm steaming about it.
"Why weren't they [signs] put up sooner?"
It may have been a case of bad timing as on Tuesday the council had changed the three large warning signs at the lake to reflect the new "red" status and installed them by 11.30am.
Council spokesman Sam Rossiter-Stead said council staff received the latest test results on Tuesday morning.
They showed the levels of potentially toxic cyanobacteria had increased rapidly from a clear situation to one of red alert.
"We took immediate action as set out in our protocol for such situations and informed the public via media release, an extensive radio advertising campaign across all stations, our website and the Greater Wellington Regional Council website."
He said as well as three large signs, an additional 20 temporary signs were put in place around the area.
"As a further measure, one of our animal control team went down to the lake [on Tuesday] to warn dog owners who may not have been aware of the situation.
"We also immediately notified Public Health, GPs and vets of the potential danger."
Mrs Lysaght said she wasn't the only one unaware of the warning on Tuesday and she saw other dogs swimming there.
Normally there was a sign right beside the path at the right hand side of the Colombo Rd entrance carpark but it wasn't there, she said.
Some other visitors to the lake on Wednesday said the signs were not obvious.
A group of kayakers from Upper Hutt who had been in the lake were alarmed when they found out. They said they hadn't noticed any warnings.
Two dog walkers also said they hadn't seen them.
