Councillor Peter Nutting, leader of Shropshire Council, has said that employing the £1,000-a-day highways consultant was the "best course of action", and that the savings outweigh the costs.
The council leader's comments are included in a written response to a question submitted by fellow councillor David Tremellen.
Councillor Tremellen had written to the authority's leader to suggest that all consultant positions should effectively be approved by scrutiny committees.
The council's decision to appoint the consultant was met with dismay from a number of politicians and Shropshire residents, although the authority robustly defended its decision, and said the role included looking at the entire highways department.
Councillor Nutting's response said: "As members will be aware, this council rarely engages consultants and only does so if other opportunities have been exhausted.
"In this case it is obvious to us all that the effective management of our highways services has been an issue for some time.
"Indeed, highways issues is the most complained about in the council.
"With respect, the Conservative Party is in power and has been elected to run this council.
"Whilst we are open to and welcome challenge through the scrutiny process we should not, and will not, make decisions through scrutiny committees, which, as members will know, is not a decision-making function of the council.
"I believe that our decision to engage this consultant was the best course of action.
"Whilst the short-term costs are significant, on balance the savings and improvement we are making far outweigh this and so the arrangement offers value for money on an ‘invest to save basis’.
"This is the key point I would make to the public, the savings and improvement we will make as a result of engaging this consultant will be far greater than the costs."
Councillor Tremellen had asked: "Before employing outside consultants, could I, on behalf of what would appear to be a substantial majority of Shropshire residents, respectfully suggest that this council submits any such proposal to whatever scrutiny committee is considered most appropriate so that this council’s own internal fund of expertise, whether in the form of relevantly experienced officers or elected members, is first examined to determine whether outside intervention is needed?"
Concluding his response Councillor Nutting commended the work of the council's roads staff.
He said: "I want to pay tribute to all of our highways staff who I know have welcomed the leadership changes we have made.
"The dedication and commitment this service has shown during the recent storms for example, demonstrates just how fantastic we can be when it really matters, and people are depending on us. Such dedication deserves good leadership.
"Sometimes when in power, tough and potentially unpopular decisions have to be made. We will not shy away from making these decisions in the best interests of Shropshire and our residents."