An official guide on how to give Leaving Cert students calculated grades is expected to be issued to teachers this week.
Details on the system of calculated grades, the alternative arrangement brought in after this summer's exams were cancelled, are currently being finalised.
The Department of Education has asked schools to have their end of the data submitted to it as close to the end of May as possible. However, educational groups have expressed doubts around this timeline.
As the first phase of the lockdown lifted today, staff are now able to access school buildings in some circumstances. Teachers can also access schools to carry out the work required for calculated grades.
Official guidance on calculated grades is currently being finalised and is expected to be sent to the teaching unions this week, according to Education Minister Joe McHugh.
"Most principals have written to parents, and I know that engagement with students has stopped," Mr McHugh said.
"The next step is for teachers to start working with the whole school community approach in terms of calculating the grades. That work hasn't started yet because the guidelines haven't come out.
"I've stated that I would like to see the results come out as close to the traditional date as possible," he added.
Once the data is submitted by schools, it goes to the Department of Education.
"We are engaging with outside expertise and there's going to be a big element of statistics around that as well.
"We're engaging with the outside expertise to ensure that we have fairness in terms of standardisation, so whether its a post-primary school in Cork or in Donegal that there is a level standard so each school knows that there is fairness built into the system.
"Once we have that model built, we're going to bring in another outside expert to ensure that there is fairness and integrity built into the system."
Both the Association of Secondary Teachers, Ireland and the Teachers' Union of Ireland have expressed concerns around the fairness and equity of using calculated grades.