A photo of Indonesian president Joko Widodo has been removed from public display at the National Portrait Gallery (NPG) in Canberra after the executions of the Bali Nine ringleaders.

The photographic portrait by Adam Ferguson was an entry in this year's National Photographic Portrait Prize.

The gallery initially planned to keep the portrait on display until June.

Gallery director Angus Trumble said its removal was a temporary measure and that the photographer had been informed.

He said they were concerned the portrait might be defaced by someone angry about the executions of Australians Andrew Chan and Myuran Sukumaran in the early hours of Wednesday.

"My feeling yesterday, on Wednesday morning, was that in view of the circumstances and our operations, and my best assessment of the risk of damage to the work of art, it was necessary to remove it from public display," he said.

"Also, I was swayed by the statements of both the Prime Minister and the Leader of the Opposition, and of course the position of the parliament and the recall of our ambassador."

Early on Thursday, Ferguson posted a statement on his Facebook page saying he was saddened to hear the news of Chan and Sukumaran's executions, but he was perplexed by the NPG's decision.

"The death sentence is archaic and my thoughts are with the families," he said.

"I was notified today that my photograph has been temporarily removed from the exhibition because of the public response to the Bali Nine executions and out of respect for the victims and their families.

"I am totally perplexed that a leading Australian artistic institution would take such action."

Discussion through art is important: Ferguson

Mr Ferguson said art was about a social and political dialogue.

The blank space left at the National Portrait Gallery after the photo of Indonesian president Joko Widodo was removed from display. ( ABC News: Matt Doran )

"Leading galleries strive to promote discussion and ask questions of their audiences," he said.

"I would have thought that allowing people to engage with the photo that I created would be now more important given the circumstances."

The portrait was taken last September during a cover shoot with Mr Widodo for Time Magazine.

Mr Trumble acknowledged that the photographer was not happy about the removal of the image.

"I rang the artist to let him know my decision and the reasons why I took it," he said.

"I'm glad that I did, we are in touch and I respect his dissenting view.

"He has said that he would rather his work were damaged or destroyed, than it be taken off display."