Judith Collins has ruled out herself or her office being involved in the website. She says if they were registering it to her office it would be a pretty dumb move.

An anonymous website backing Judith Collins for National Party leader is registered to her electorate office address, a fake phone number, and what appears to be a fake identity.

The now-deleted website BackJudith.nz said it is "in no way endorsed by the National Party formal hierarchy, or Judith Collins" - a view Collins echoes.

But a domain name lookup on the service whois has the website registered to her office address with the phone number +64 123456789.

The electorate office address is publicly available and there is nothing to stop a person not associated with the office using it.

Since Stuff published a story on the topic the website appears to have been deleted.

The name associated with the registration was Raquel Ray.

The homepage of the website BackJudith.nz.

There is no online or ownership records of a Raquel Ray in New Zealand, save for a recently set up Facebook account and a smattering of Official Information Act requests to Callaghan Innovation.

That Facebook account - which has posted a link to the BackJudith website - has a profile picture also found on a photography website.

That photographer told Stuff the person in the photograph was someone else not named "Raquel Ray".

Stuff has sent an email to the address listed in the website's domain.

Collins herself said she and her office had nothing to do with the website.

"Well I know that nobody in my office would actually be able to do that," Collins said.

She assumed it was someone who really did want to support her and simply remain anonymous.

"I presume it's not someone trying to cause difficulty for me."

If her office had set it up secretly "using my work address would be a really dumb thing to do."

The website encourages people to sign an open letter to National MPs to back Collins for the leadership.

"I am a member/supporter of the National Party and am concerned about the future direction of New Zealand under the new Labour, NZ First, Green Coalition Government," it reads.

"I believe Ms Collins is the best option for our Party - to deliver a victory in 2020 and deliver another strong, stable, National-led Government to lock in our economic success and stability."

At the time of writing 388 people appeared to have signed the letter.

The NZ Taxpayers Union have run a campaign around Callaghan Innovation expenses.

Director Jordan Williams said they had a "Raquel Ray" in their database as someone who had sent in tip-offs in the past.

Williams said he and his staff were not at all involved in the website.