Fire and Emergency said three helicopters with monsoon buckets and seven ground crews were still working hard to eliminate hotspots ahead of a windy forecast on Saturday.
Fire and Emergency received a call about the fire at about 11pm on Thursday and the first crews were onsite 10 minutes later.
By Friday morning the fire had burnt through 10 hectares of vegetation in Whitireia Park, Fire and Emergency said in a statement.
Fire crews will be on the scene throughout the day and overnight, with more teams likely to be brought in tomorrow.
A drone crew will help identify hotspots on Friday afternoon.
Incident controller Steve Hudson earlier told Morning Report the 10-hectare blaze covered very hilly terrain, and strong winds overnight had helped the flames to spread quickly.
Firefighters were hoping the forecast dropping winds would help the situation, but there were a number of houses that could be in the firing line if the wind changed, he said.
"We're at the top at the golf course at Gloaming Hill, Titahi Bay. There are a number of properties that are along the top of the ridge, they would be our concern if the wind changed and started crossing the gully where the fire currently is.
"So we have spare crews available to respond to exposure protection if that happened."
Hudson said it was still unclear how the fire started.
"We roughly know where it started but we've asked for a specialist fire investigator from the Wairarapa to come in and do an assessment once it's safe enough to enter the area."
Fire and Emergency said additional rural firefighters were being brought in to support and relieve the urban and rural crews who had been working overnight.
Smoke is affecting a large part of Porirua and the Public Health Service said those who are affected should go inside and close the windows and doors and turn off air conditioning units.
"The smoke is drifting across Porirua Harbour and people have been smelling it ... in the Hutt Valley and further afield as well, even in parts of Wellington in the early hours of the morning," said Hudson.
"We actually fielded a lot of 111 calls to smoke in those areas but after investigation it was deemed that the smoke was coming from this fire."
Porirua mayor Anita Baker said Fire and Emergency had the situation under control but people needed to stay away from the fire site.
Smoke could irritate the eyes, nose, throat and airways and smokers, the elderly, children and those with asthma, heart or lung disease were most at risk, said the Public Health Service.
