The remains of 280 people were discovered by archaeologists excavating a medieval friary beneath the former Ocky White site in Haverfordwest, to make way for the £6m project.
Dyfed Archaeological Trust started digs at Bridge Street after human remains were found during demolition works to prepare the location.
Experts believe the ruins were from St Saviour's Friary, founded by a Dominican order of monks in the 13th century, and was in use until the 16th century.
Around half of the skeletons found in the ancient burial ground belonged to children.
Some councillors at Pembrokeshire County Council are concerned the discovery of the remains could have resulted in an overspend on the development.
That will be addressed during a council meeting today where Councillor Clement is expected to ask for a full costs update.
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know…