It comes as the Liberals have promised an inquiry into the handling of hazardous materials at the school and parents have demanded more transparency.

Complete Constructions was engaged to replace windows in eight classrooms during the July school holidays, work which was not deemed to be a lead process by Robson Environmental.

Children in preschool, the Montessori school and year 3/4 spent the first two days of Term 3 in their usual classrooms before test results were processed and revealed cleaning had not sufficiently reduced lead contamination levels.

Further testing uncovered above-threshold levels of lead in three other rooms in the school where dust had accumulated on high surfaces.

All rooms in the main school building and the after school care are now open but rooms in the Gambari Centre and Montessori school remain closed for a fifth straight week.

Opposition education spokeswoman Elizabeth Lee said if elected the Liberal party would instigate an independent inquiry into the handling of hazardous materials at Yarralumla Primary School and an infrastructure audit of all ACT public schools.

"There are lots of issues and concerns that have been raised about our failing infrastructure in our city's government schools," she said.

"Lead is obviously a great concern here at Yarralumla Primary, but we've also seen instances of asbestos, of mold, of leaks and of plumbing issues. So, it isn't just limited to lead paint and it isn't just limited to Yarralumla Primary."

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Education Minister Yvette Berry said she visited the school last week to better understand the impact of the issues.

"The government is responding to lead based paint at Yarralumla Primary School in line with expert advice and will continue to upgrade and improve public school infrastructure if re-elected, with more than $115 million spent over the last four years".

Some parents claim they were not informed about a lead assessment from April 2019 and a lead management plan from November 2019.

An Education Directorate spokesperson said letters had been sent to parents about lead remediation work in July and September last year. They said it was standard practice for hazardous materials management plans to be available through the school office. An updated lead management plan is expected next month.

"An offer is being made to the Yarralumla school community for senior executive staff in the Directorate to walk them through these reports so they can understand them in context and the work being done to respond to them," the spokesperson said.

Abigail Fargher, who has two children at the school, said she wanted to see the recent lead testing results.

"It's just hard to make an informed decision about whether it's a safe place or going to be a safe place going forward until we see those [reports] and have all the information."

Sam Mudge, who also has two children enrolled, said he was not aware of the lead reports until last week.

"We heard from the Directorate the contractor that was responsible for that building was the one that made an error and the Directorate even confirmed that they wouldn't be using that contractor again."

Complete Constructions and Robson Environmental were contacted for comment.