The Western Australian Museum has been accused of glorifying vandalism after it acquired a piece of clear perspex that once protected an iconic Australian painting which was graffitied by climate activists.

Climate activist Joana Partyka, 39, spray painted a Woodside logo on the acrylic covering of Frederick McCubbin's celebrated 1889 work 'Down on His Luck' in January last year, in protest against Woodside Energy's $16.5 billion gas project in the Burrup Peninsula.

Partyka, who is from the Disrupt Burrup Hub protest group in Perth, was arrested, fined $2,500 and ordered to pay $4,800 to the Art Gallery of Western Australia after being convicted of causing criminal damage. 

The museum has now acquired the piece of perspex from the art gallery as part of its collection, prompting debate about whether it is endorsing vandalism.

Both sides of politics are united on the issue. 

Deputy Premier Rita Saffioti said it was not something she would do if she were calling the shots at the WA Museum.

'Throw it in the bin'

Ms Saffioti likened the move to the state government keeping its vandalised train carriages.

“We don’t keep our train carriages that people have graffitied, we don’t do that, we clean the graffiti off because it's illegal behaviour,” she said.

When Liberal leader Libby Mettam was asked at a press conference what should happen to the piece of glass, she gave a clear instruction.

“Throw it in the bin,” Ms Mettam said.

State Opposition Leader Shane Love shared Ms Mettam's disapproval and said displaying the perspex "would have given a terrible message to Western Australians that that sort of vandalism is acceptable and that people can act in that way."

Museum chief executive Alec Coles said the piece would be kept in storage and would not be on display anytime soon.

"We've got something like eight million items in our collections and in that you will find items that refer to events that are controversial," Mr Coles told ABC Radio Perth.

"Whether it might be protests against the draft for Vietnam, whether it's people arguing over the plebiscite, on gay marriage and so on, it's part of what we do, we document these things."

Mr Coles said the perspex was an important part of the state's history and could one day be used to represent a point in time, irrespective of whether people agreed with the protest or not.

"By collecting this piece, we're not legitimising either the cause that it represents or indeed the action that we clearly condemn," he said.

"Museums these days are much more interested in collecting lots of different viewpoints and representing them because we don't know in five or 10 or 50 years time, how people will be assessing these events or wanting to reflect on them, or maybe even wanting to make exhibitions about them."

He also quelled concern about the use of taxpayers' money to acquire the piece of perspex, saying it did not cost the museum anything.

McCubbin family supportive

The great granddaughter of the artist released a statement on behalf of McCubbin's family, siding with the museum.

"It is the museum's job to collect material significant to our state's cultural life," Margot Edwards said.

Given her great grandfather's artwork was protected, Ms Edwards said vandalising the perspex was an effective way to protest Woodside's actions.

"Our ancestors across generations left an iconic artistic narrative on the impact of colonisers on the Australian bush," her statement read.

"As an act of protest drawing attention to the impacts of the expansion of fossil fuel extraction in our north-west, on the priceless ancient indigenous cultural heritage of the Burrup Penisula, the perspex on McCubbin's painting was an effective palette for this radical protest."