Police were alerted to the theft from the Wollongong City Memorial Gardens and Crematorium yesterday morning by Wollongong City Council staff.

Police found 477 small bronze vases - attached to memorial plaques to hold flowers - had been torn off walls and stolen, leading to the damage of 56 memorial plaques.

"They were stolen from three areas of the garden, from two walls of the memorial and also from the ex-servicemen's area," Inspector Paul Allman, of Wollongong police, said.

Lord Mayor Gordon Bradbery said the attack had been planned and intentional.

"They used a hacksaw or maybe just broke them off the wall," Cr Bradbery said.

"The vases are only small, but when you have 477 of them, that really adds up to a considerable amount.

"This was planned, it was not impulsive."

Police suspected the thieves targeted the vases for their value to scrap metal merchants.

A spokesman for one Wollongong scrapyard said bronze could be sold for up to $4.50 per kilogram.

"We already have made inquiries at local metal dealers, as we suspect the thieves will fence the material for scrap," Insp Allman said.