The Wanganui Ratepayers Association is concerned about the cost of the Sarjeant Gallery redevelopment and the burden it is placing on ratepayers.
Association chairman Dave Hill estimates that as much as $10.6 million of rates money could go into the project - "a project we were told would only go ahead if we sourced the money from outside Whanganui".
The upgrade and extension of the building has been put at $34 million-plus and, with funds from central government and various grants, the Sarjeant Gallery Trust is about $3.9 million short with a December deadline looming.
Whanganui District Council has agreed to under-write that sum to ensure the project goes ahead.
Mr Hill said this week ratepayers had already stumped up $2.7 million in October 2014 for the temporary Sarjeant on the Quay gallery which is operating while the upgrade on the iconic Queen's Park building is completed.