The open day, part of Heritage Week, will kick off at 9.30am with tours, historical talks and Devonshire teas on offer until 1.30pm.

Friends of St Thomas’ Church heritage volunteers will be on hand to guide visitors through the building and up to the bell tower revealing hidden secrets and historical stories along the way.

Archivists and historians Lorryl Rumble-Fuller and Carol Chandler have devoted hundreds of hours researching the church’s history and restoring treasured photographs and artifacts found on the site.

St Thomas’ Anglican Church was built by convict labour under military supervision when Australia was still part of the Diocese of Calcutta and Port Macquarie was a penal settlement.

The foundation stone was laid in 1824 and the first service held in 1828. Many of the convict bricks used in the church’s construction can still be seen in the foundations today.

More than 365,000 handmade bricks were used to construct the walls which are up to three feet thick at the nave.

The mortar, made from oyster shells, was transported from Limeburners Creek on the North Shore of the Hastings River.

The original floor was constructed from rammed earth but nine inch paving bricks were laid in 1846.

All of the timber, apart from the 40 foot bearers in the ceiling, is locally hewn cedar.

With the arrival of free settlers, farmers, merchants and government officials, the congregation at St Thomas’ grew. With this came the box style pews for which parishioners paid rent until the system was abolished in 1905.

Beneath the floor of the front pew is the grave of Captain Rollands, who died of sunstroke and was buried a month before his second in command laid the foundation stone during a service conducted by the Reverend Thomas Hassall.

The site was also home to the region’s first National School, housed a doctor’s dispensary and is perched a top on old oxide mine.

The open day is free to the public.