Police were examining the scene as if it were a homicide - "that's just the detail we put into the investigation'' - but were not seeking anyone else.
The Webster home was being forensically examined and their bodies were expected to be removed from it late this afternoon, with post-mortems likely to be conducted tomorrow.
"We've had some contact with the extended family and ... they're very lucky. My initial take on them is that they're a very close family, they're very strong and they're very supportive of each other,'' Mr Oxnam said.
Mr Webster was a local Community Board member and the couple ran a seasonal nursery called Paradise Plants.
A local man said the nursery opened between spring and Christmas but did not open last year.
Kapiti Coast councillor Hilary Wooding, who also sat on the community board with Mr Webster, said he would be "hugely, hugely missed''.
Fellow board members had become aware of his cancer only recently.
"Until about a fortnight ago he was at meetings and commenting and making good statements, so obviously things took a huge turn for the worse, probably sometime at the end of last week,'' Ms Wooding told APNZ.
"We hadn't expected this to happen in the way that it seems to have happened.''
Ms Wooding said Mr Webster would be missed both personally and for his work with the community.
"He's made a huge contribution, both to Paekakariki but also to Kapiti as a whole.''
Another board member, Helen Keivom, said most people would only know a fraction of what he had done for the community.
"To lose Adrian and Marei is absolutely heartbreaking and shock doesn't begin to describe it.
"We have lost two wonderful people whose love for Paekakariki and tireless commitment to ensuring our community got the best outcome is unparalleled.
"Many people in the community only know a fraction of just how hard Adrian, with unflagging support and advice from Marei, has worked as chair of the Paekakariki Community Board and his loss will be felt keenly for many years to come.''
Mr Webster was "a dear friend and a mentor and a guide'', Ms Wooding said.
A woman who lived nearby said she was in shock.
"It's such a tight-knit community,'' she said.
A local shopkeeper said Mr Webster was well-liked and respected in the community.
The Paekakariki market, held on the first Saturday of each month, has been cancelled as a mark of respect.
A couple with a bach near the home said the Websters were "a lovely couple''.
"That's so sad.''
