Surging crowds to the Powerhouse Museum have cruelled government claims that it must be moved to Parramatta to arrest its "rapid decline", with visitors to its inner-city site growing by a third.

Almost 570,000 people visited the Ultimo museum in 2015-16, a 33 per cent increase on the previous year. The Powerhouse's performance outpaced that of the Art Gallery of NSW, Australian Museum and Sydney Opera House.

Popular exhibition The Art of the Brick: DC Comics helped to drive visitor numbers at the Powerhouse Museum. Credit:Peter Rae

The strong result countered repeated claims by Arts Minister Troy Grant that the museum was in "rapid decline" and must be moved west because fewer people were using it.

Greens MP David Shoebridge, who is deputy chairman of a parliamentary inquiry into museums and galleries, said the Powerhouse's soaring patronage showed the government should scrap the controversial move.