The exhibition comprises of both new and recent works by the artist, many of which can be seen for the first time in the town.
The scheduled opening in January was delayed because of lockdown and now the exhibition is to be extended until September 5.
Featuring both paintings and prints the exhibition will be the largest presentation of the artist's work in a UK public gallery to date.
It offers people the rare opportunity to view a significant body or work by the artist.
Described as rich in detail, colour and texture, each work is conceptually rigorous in its interrogation of the world around us.
It draws together source material ranging from designer fabrics and jewellery to the natural world, from the histories of art and literature to popular culture.
The exhibition includes a work, entitled Flowerings of the Chocolate Cosmos, which was painted during lockdown.
Anj Smith is regarded as one of the UK's leading contemporary artists and the exhibition will be accompanied by a publication with essays by Dr Joost Joustra and Dr Zoe Whitley.
Chris Wilkinson, marketing officer, said The Gallery had been temporarily closed since December because of the second Government lockdown.
She said: "We are looking forward to welcoming visitors back to the gallery and are committed to making visits safe.
"The Gallery is following health and safety advice with additional measures and standards in place to ensure visitors have an enjoyable and safe visit."
An online event, entitled In Conversation with Anj Smith and Dr Zoe Whitley, is to be staged on May 25, from 5pm to 6pm, and anyone interested is being asked to register.