Arrowtown's Athenaeum Hall will close for two months over winter for strengthening work and an upgrade that will return the building to its full capacity.
The work will include essential earthquake-strengthening, upgrading the toilet facilities, installing a new heating plant, public address system and ablutions area.
Some of the extra work triggered the need for additional pre-construction reports and consultation with heritage groups, which delayed the start of the renovations and strengthening, that were originally scheduled to be done in May, a council spokeswoman said.
The hall was built in 1870 and had significant alterations carried out in 1991.
Its usual capacity of 500 people was temporarily reduced to 300 in February 2015 after a seismic assessment.
The earthquake-strengthening would enable the hall to once again accommodate up to 500 people.
The work is expected to begin in early July and is likely to be completed in late August.
QLDC chief executive Mike Theelen said the council apologised for any inconvenience the change in dates caused users, but said the outcome would be an improved facility for the community.
