After making nearly 1,200 staff redundant, the further education funding body now finds it has 712 vacancies in positions from administration to contract management and strategic planning.
It has blamed the staff union for resisting plans to advertise many of the posts, but union leaders said there are hundreds of employees who should be given the chance to change jobs or re-train first.
In a bulletin to staff last month, the LSC said: "We are concerned about the level and numbers of vacancies and will continue to discuss the external advertising of the critical roles, particularly where there are no internal candidates."
More than a third of the vacancies are considered to be critical by the funding body, but the Public and Commercial Services union only agreed to advertise two of them initially.
The LSC said it has now won an agreement which means that almost all of the 247 critical vacancies can be advertised.
Under a deal brokered during discussions about the mass redundancies which were prompted by the LSC's Agenda for Change reforms, vacancies can only be advertised externally if the union agrees. Sally Stewart, human resources director at the LSC, said the work of the funding body would not be affected by a vacancy rate of more than one in six staff.
"We have perfectly adequate resources to carry out the work we have to do,"
"We have a lot of people leaving us, but many are working until January next year and some even later than that. We are working to fill them as soon as we can. It's a significant but not overwhelming number of vacancies."
But the PCS said the funding body still appeared to be dragging its heels on redeploying existing staff.
Lynn Smith, vice-president of the PCS union's LSC group, said: "To have 700 vacancies in an organisation that has lost nearly 1,200 posts - it's just difficult to understand the rationale.
"I genuinely don't believe there are 700 people out there who want to join the LSC and who have got the skills to work there."
The job cuts under Agenda for Change are intended to streamline the LSC, providing an extra pound;40million a year for education and reducing centralisation.
It will also mean creating new local partnership teams which will work more closely with colleges, and economic development teams to focus on employment and regeneration.