The news was announced at a meeting of the town commissioners earlier this week.
The closure is due to take place between 29 April and 6 September.
It comes after a public survey which showed 65% of respondents supported the idea of creating an open space in the town centre.
MHK for the area, Jason Moorhouse has called it a "momentous decision" but added that local traders are concerned it could impact business.
He added: "The more we can do to make this plan work and to support local businesses, the better it will be for everyone".
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