The exhibition, Collection Highlights will feature a range of artworks from the gallery's permanent collection.

Gallery director Bradley Hammond said it was initially thought the gallery would close for construction earlier, however the building tender process is still underway so the closure date was pushed back.

"We are still doing the extension, we just don't need to close when we thought we would," Mr Hammond said.

"We will be closing at the beginning of April after FOOD Week through to November ... unless the builders tell us we have to close earlier.

Mr Hammond said he would know more about the timeline for the build once until a successful tender is announced.

"We've worked with [architect] Sam Marshall who did the extension to the Museum of Contemporary Art in Sydney," he said.

He said a key part of the design was directing natural light, as well as having a contemporary exhibition space, a 77-seat theatre, an exhibition space for the gallery's collection as well as space so the art collection could expand in the future.

Mr Hammond said work has started on planning new exhibitions to be displayed once construction is complete.

Mr Hammond said the gallery had a magnificent collection that had been bequeathed, donated, and purchased through community fundraising over the years.

"The acquisitions are often supported by friends of Orange Regional Gallery along with the Orange Arts Foundation so it's thanks to their support that we are able to purchase new works for the collection," he said.

He said Collection Highlights would present some of the iconic and well-loved works from the Mary Turner and Chroma collections, as well as from the general collection, in addition to recent acquisitions.

"The collection is an expression of generosity, philanthropy and community working together," Mr Hammond said.

"We had in mind that we would do a permanent collection exhibition.

"There are some recent acquisitions that people may not have seen yet and also people will be seeing works that they may have seen before but in a different context.

"This is the first time people are seeing works from Mary Turner and Chroma side by side."

Mr Hammond said the artworks would not be hung chronologically so people would see art by minimal colour-field artist David Serisier alongside 20^th Century pieces by Hans Heysen and Roland Wakelin.