A group of climate change activists behind a stunt that saw protesters glue themselves to a prized Picasso painting in Melbourne has apologised for the incident.
A 59-year-old man and a 49-year-old woman were arrested but released without charge on Sunday for tampering with the artist's 1951 anti-war painting known as Massacre in Korea at the National Gallery of Victoria.
While the loaned piece was not damaged, a spokeswoman for Extinction Rebellion said the environmental protest group regretted the inconvenience the stunt caused.
"People can believe we're idiots all they want and maybe we are idiots, who knows? We admit that this is the sort of thing that is inconvenient for people, we don't like doing this sort of thing to people - we feel bad about it and we are so sorry," Catherine Strong told ABC Melbourne radio on Monday.
The two protesters superglued their hands to the painting, which is part of the gallery's Picasso Century exhibition.
The exhibit was temporarily closed to the public as police responded.
The duo's hands were safely removed from the protective perspex and there was no reported damage to the work.
The purpose of the stunt was to raise awareness about the global impacts of climate change.
Retired teacher Tony Gleeson was one of the two protesters who were arrested by police.
"I am taking this action today because art is one way to connect us to the emotional side of human suffering, and to increase our empathy," he said in a statement on Sunday.
"This painting represents the suffering of war. We need to be thinking about how this type of suffering will increase and how the societal breakdown that scientists are telling us is coming will eventually put us all in the firing line."
In 1986, Pablo Picasso's The Weeping Woman painting was stolen from the same gallery and later found by police in a locker after an anonymous tip-off.
The gallery purchased the work for $1.6 million. The case remains unsolved.