The parents of a teenager who drowned in flash floods in Auckland on Saturday say he was taken "at a time when the world was just opening up to him".

Mitch Woolley, 17, died alongside his school friend Sosi Turagaiviu after trying to cross a swollen river in West Auckland's Waitakere Ranges in the late afternoon. Their bodies were recovered later that evening.

Mitch had just left Massey High School and was about to start an apprenticeship as a marine engineer.

COLIN ENNOR The Waitakere Ranges' placid streams turned to raging torrents on Saturday afternoon, taking the lives of two teenage boys.

"He had worked from the finish of the school year at a local business, and was about to start his journey," parents Tracey and Mike said in a statement on Monday.

READ MORE: Waitakere flash flood survivor recalls 'crazy white water rapids'

Mitch was also a keen surfer who had recently travelled to Germany on a school football trip.

CHRIS MCKEEN/STUFF Two 17-year-olds lost their lives after flashing flooding tore through the Waitakere ranges.

"He was always the cheeky and fun loving entertainer in any group.

"Mitch's infectious personality always ensured that there was a smile on the faces of family, friends and those that happened to meet him."

At the Massey house where 17-year-old Sosi lived, family and members of the wider Fijian community gathered on Monday night to pray, sing and remember a young man full of potential.

COLIN ENNOR A flash flood in the Waitakere Ranges claimed the lives of two other walkers who tried to cross the swollen stream.

Sosi was due to start his final year at Massey High School on Wednesday, and pick up a new car on Thursday, family members said.

His father, who had been working in Australia, was on his way home, while other family members were flying in from Fiji.

The boys had spent Saturday with Mitch's twin brother Denver and two other friends, both 17-year-old boys, in and around the Waitakere ranges.

It was a place Mitch "lived in and loved, surrounded by the bush", his parents said.

Tracey and Mike Woolley also paid tribute to Sosi, saying they wanted his family to know they were thinking of them.

"The boys spent many good times together," they said.

"Finally we would like to thank the police, and emergency services for bringing our boys home and the Waitakere golf club for their support during the search."

Principal Glen Denham said both teens were both "vibrant, passionate young men who involved themselves fully in all aspects of school".

Both were talented sportmen – as well as football, Sosi was a keen basketballer, and Mitch played and coached waterpolo.

Denham said his sympathies were with the boys' families and friends.

"They will be sadly missed at Massey High School and never forgotten."

The school was closed on Monday and Tuesday, but Mitch and Sosi would be remembered at year level assemblies on Wednesday, Denham said.

Students would be offered support through the guidance department.

Josiah Brown had played soccer with Mitch since they were children, and said he was the "stellar goalkeeper" of their summer team this season.

"Mitch was a kind fella ... that made people smile by just being himself," said Brown.

"He was genuine and caring. He wore his heart on his sleeve especially when he played his football. He brought joy to all those around him and he is going to be greatly missed."

Denver, who was also on their team, survived Saturday's tragedy.

He, too, was washed away by the freak flooding but managed to cling to some foliage while waist-deep for two hours before being rescued by the Westpac helicopter.

Denver was winched to safety but had suffered several abrasions. The helicopter crew said he was also cold and very fatigued before taking him to Middlemore Hospital

The Ranui Swanson Football Club paid tribute to Mitch and Sosi on its Facebook page, sending "love and support" to the teens' families.

"It's never easy when someone passes, but when its a young person it is so much harder to comprehend," it posted on Sunday, after the victims' names were announced by police.

"Today's news saddens me to hear that two young footballers lost their lives this weekend. Mitch and Sosi, you both will be greatly missed."

A friend of Sosi said it was hard to believe he was "not with us anymore".

"You were the brother that was there for me 24/7 when I got in trouble ... you came running in the rain with an a umbrella just to see if I was ok, the best brother I never had," he wrote.

"Just knowing you was a privilege because you were so humble and generous and everything we did together is just hitting me right now."

The two deaths have been referred to the coroner.

TRACKS CLOSED AFTER FLASH FLOOD

A number of walking tracks in the ranges have been closed until further notice following the deaths, and people are being urged to stay away.

Auckland Council's western principal ranger Stephen Bell said the flash flooding had destroyed the lower suspension bridge on the Cascade Stream, and damaged another bridge further along the Auckland City Walk.

"Due to the extent of the damage, and in the interests of public safety, we've closed the tracks at the Cascade Kauri end of the ranges, including tracks that lead into the area," he said.

Park rangers had erected closure signs and 'danger' tape at the start of each track.

"We are now undertaking a thorough review of the track network and infrastructure around Cascade Kauri and Piha, as that area was also hit hard by heavy rain and high stream levels," Bell said.

"This will take some time and we're urging the public to stay clear of the areas that have been closed off."

The Falls Rd gate had also been locked.

The areas closed to the public are:

Fence Line track and access from the dam face of the Waitakere Dam Rd track

Smyth Ridge track

Wainamu Bush track from Smyth Ridge

Ridge Rd track

Long Rd

Whatatiri track from Long Rd

Andersons track, Wainamu Bush track, Pukematekeo track, and West Tunnel Mouth track have already been closed to prevent the spread of kauri dieback disease.