A North Shore police spokesman said: "He managed to get a hold of his dog and started swimming towards the shore, however he got into some difficulty.
"Two bystanders entered the water to try to help him. They pulled him to the shore. They started CPR until [the ambulance] arrived but he never regained consciousness and he died at the scene.
"He was walking with his wife."
Mr Lewis ran his own company, Peter Lewis Carpet Services.
At his home in Wairau Valley yesterday, his grey work van was parked in the driveway as family members stood outside.
Those who spoke to the Herald said it was a difficult time for the family but particularly Mr Lewis' wife, who did not want to talk about the accident.
His Facebook page shows his hometown as Burnley, Lancashire and he has written on his page: "Celtic, Welsh, Irish but Lancashire lad - and now a proud Kiwi."
In a notice published yesterday, Mr Lewis' family paid tribute to him and also acknowledged that he had died "in a tragic accident".
"Loved husband and best friend of Ruth. Brother of Gillian, special uncle of Eddie and Rory. Loved by his extended family."
A service to celebrate Mr Lewis' life will be held on Friday.
Mr Lewis was one of four people who drowned during the Easter holiday. Another man - aged in his 30s - also drowned near the refinery in the early hours of Sunday morning.
additional reporting APNZ