The Prime Minister's office has complained to a leading women's magazine after it digitally altered a picture of John and Bronagh Key for its earthquake edition.

Woman's Day did a photo shoot with the couple for its Valentine's Day edition last month, in which Bronagh Key was wearing a silky peacock-blue Helen Cherry top.

Last week, it ran a front-page story headlined "John Key's message of hope", with a photo of the couple.

In the week after the earthquake, John Key had divided his days between Wellington and Christchurch. He had little time for a photo shoot in Auckland with his wife.

So the magazine ran a photo of John and Bronagh from the earlier sitting - but with the colour of Bronagh Key's top miraculously changed to red.

The Prime Minister's office would say little on the matter.

"We are totally immersed in our response to the tragedy that is the Christchurch earthquake," a spokeswoman said. "Any issues that we may have had with this publication have been taken up directly with them. We will not be commenting further."

Staff at Workshop, which stocks Helen Cherry, said there had been a lot of chatter about the top's sudden change in colour.

But Paul Dykzeul, chief executive of ACP which publishes Woman's Day, said he had been in touch with the Prime Minister's office and "there is no issue with it".

He accused the Herald on Sunday of having a vendetta and said all media publications "Photoshop" pictures.

When asked if that photograph had been altered, he denied all knowledge.

"This is just a straight set-up," he said. "You Photoshop shots all the time.

"I spoke to the acting editor today and she was quite surprised. We're in a competitive world."

When asked if Helen Cherry could take exception to having her creation digitally altered, he said: "Is the issue about the garment? We did not change the design at all."

Editor's note: In accordance with Press Council principles, the Herald on Sunday discloses any material changes to published photographs.