He said NRC was keen to sell the property this year.
The 9967 sq m site consists of 12 lots and as at September 2015 was estimated at $5.5 million by homes.co.nz.
"The reality is it was important in the last 12 to 18 months that we work with the (Whangarei) District Council in road widening works and it would have been very unwise for NRC to market the property was the road works were ongoing," Mr Heatley said.
NRC, through the Public Works Act processes, provided a small portion of its land on the building's site at the intersection for road works.
It also leased an area of the vacant site to a road construction company's vehicle and equipment during the road works.
Initial plans by the regional council to develop the site as a medical precinct were stalled after the sale of the building for use as a medical centre fell over.
NRC then pursued investment opportunities, and called for expressions of interest from potential joint-venture partners to redevelop the former supermarket site.
The 9967sq m site consists of 12 lots and in late 2014 had a land value of $3.635 million and capital valuation of $5.625m.
The site was originally bought as a commercial investment and had not been inherited from the former Northland Harbour Board, as had other council properties.
Last year the NRC turned down a proposal from Whangarei disability support group NorthAble to buy the property and turn it into a medical precinct.
NorthAble offered NRC $2.4m for the site but the council instead decided to go with its own plan for a medical precinct there.