The Australian Memorial at Wellington's National War Memorial Park is made from rock sourced from India.

They are supposed to stand for the red earth that Australia's servicemen left behind when they went off to war.

But the 15 sandstone columns at Wellington's new war memorial park are as Australian as the Taj Mahal.

Australia's Department of Veterans' Affairs has confirmed the columns, which are at the heart of the Australian memorial formally opened by prime ministers Tony Abbott and John Key on Monday, are made of stone quarried near Agra, the home of the Taj Mahal.

Cameron Burnell/Fairfax NZ Wellington man Dominic Trewavas says using Indian rocks at the Australian Memorial at Pukeahu The National War Memorial Park ''wrecks the whole narrative'' and it should be pulled down.

Abbott appeared blissfully unaware the stone was Indian when interviewed by breakfast radio host Alan Jones on his return to Australia on Tuesday.

Jones asked him about the trip, to which Abbott replied: "It's the first foreign war memorial in New Zealand. It's a magnificent memorial. It's basically columns of Australian stone."

Office of Australian War Graves director Chris Appleton, from Veterans' Affairs, was master of ceremonies at Monday's dedication of the $5 million monument, which is part of the Pukeahu National War Memorial Park.

When the project was first begun, experts tried to find red Australian rock, he said. They looked at possible sites in Victoria, Tasmania, and two in the Northern Territory.

"We couldn't source the quantity and quality we wanted in time."

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A quarry would have needed to be set up to get the necessary 300 tonnes of stone out, he said.

In the end, the stone was sourced from India. But Appleton insisted it was almost identical to that which would have come from Australia, as both countries were originally part of the ancient land mass of Gondwanaland.

He said the decision to go with Indian rock was made in 2013, and was "nothing to do with the New Zealand". He would not say when the New Zealand government was notified about the change of plan.

However, a spokeswoman for the Ministry for Culture and Heritage confirmed on Monday night that it had known about the Indian stone since at least October 2012.

Arts, Culture and Heritage Minister Maggie Barry said the Australian Government was responsible for the memorial's design and sourcing of materials. "I think it is a very suitable monument to our Anzac links, and has already become a popular attraction within the park."

But those at the park on Monday were less impressed. "It wrecks the whole narrative they are trying to represent ... I reckon pull it down now," Wellingtonian Dominic Trewavas said.

Roger Smeaton thought it was "OK", but the stones should have come from Australia.

Graeme Moran was at the site earlier in the day, when Abbott said the plinths "represent the red heart of Australia".

"I suppose it is not Australian, but whatever," Moran said.

The memorial was designed by Australian architects Tonkin Zulaikha Greer, and was meant to interweave Australian sandstone with New Zealand grey basalt.

The company would not comment when contacted on Monday. Its website describes the memorial as a "landform of Australian red sandstone, forming an iconic and appropriate place of memory and reflection, embodying the Australian character and responding to the urban and heritage qualities of the site".

However, the Veterans' Affairs website is rather less specific, stating merely that the columns are "symbolic" of Australia's Red Centre.

David Moger, chief executive of the New Zealand Returned and Services Association, said it appeared the Australians had done everything they could to make the columns authentic.

Failing to source homegrown rock was "not ideal", but it was the red imagery that was more important rather than the origin of the rock.

The design of the Australian memorial, by architects Tonkin Zulaikha Greer in conjunction with artist adviser Janet Laurence, was chosen from a competitive tender process.

Each of the 15 columns is six metres tall and is made up of 10 sandstone blocks, each with a core of steel.

The columns are surrounded by a type of eucalyptus tree known commonly as the red flowering yellow gum, which grows in western Victoria and coastal South Australia. When mature, they will be about 10 metres high.

The memorial is a counterpart to the New Zealand Memorial on Anzac Parade in Canberra, which was opened on Anzac Day 2001.

The design and construction of the memorial was covered by the Australian Government, but after Monday's official dedication, possession passed to the New Zealand Government, which will pay for its upkeep.