MERRIMACK — Town planners are raising concerns about the second phase of the John J. Flatley Company’s mixed-use development project along the Daniel Webster Highway.

The main issue is focused around a new road intended to connect the residential component of the the project with the retail section. The developer said last week that it is willing to build a temporary gravel roadway, but does not immediately intend to spend $1.5 million or more on a newly paved road this early in the project without having tenants lined up that may need to alter the roadway design.

“We are contemplating a substantial commercial development — a large investment,” said Chad Branon with Fieldstone Land Consultants of Milford. He said a new, 2,300 foot roadway that costs upwards of $1.5 million is an investment that might halt the project from moving forward.

Branon asked town planners to amend a previously approved conditional use permit that would allow the roadway connection to be constructed in the future — not during the second phase of construction that is about to get underway.

“We obviously need some leeway development wise,” echoed Kevin Walker with the Flatley Company.

The entire Flatley project, once complete, will convert nearly 150 acres of land next to Saint-Gobain Performance Plastics into 240 apartments, 300,000-square-feet of retail space and 120,000-square-feet of industrial space; the future retail space will require its own individual site plans and additional approval from the planning board.

Five residential buildings to accommodate 240 one- and two-bedroom garden-style rental apartments, a pool, tennis courts and clubhouse are included in the plans, although the first phase of construction includes four residential buildings. Town permits have already been granted for the first portion of the project.

Last week, the planning board asked the developer if it would be willing to construct a temporary gravel roadway to connect the four apartment buildings now under construction with the future retail space if the board allows it to construct its fifth apartment building now.

Walker obliged, however nothing formal was voted on and representatives with the Flatley Company were asked to meet with town staff and fire officials to work on the specifics of the roadway design.

A local fire official said the new roadway is necessary before the fifth apartment building is constructed in order to provide emergency crews a secondary access to the development.

“I am certainly not convinced, in the current situation, that you will ever get anybody in that big box store … I just don’t see it,” said planning board member Alastair Millns.

The conditional use permit is designed to integrate retail, commercial and residential, he said, adding that without a roadway connection, the objective of the permit is not being met.

“I am still concerned you are not going to have the integrated aspect,” agreed town councilor Tom Koenig.

The four apartment buildings are already under construction, and Walker said the retail area is now being designed.

“We are in this for the long haul,” he reassured the board.

The topic will be revisited later this month at a Jan. 22 meeting.