Major water, ventilation and drainage checks are to be carried out at the long-awaited children's hospital in Edinburgh.

Health secretary Jeane Freeman announced a raft of measures for the new Royal Hospital for Children and Young People (RHCYP) after its opening was cancelled at the 11th hour earlier this month.

It was due to open on the same day as the old Sick Kids hospital in the capital closed, until a problem with the ventilation system was discovered in its critical care unit.

NHS National Services Scotland (NSS) will assess in detail "all building systems which could impact on the safety of patients and staff" at the new site, officials said on Thursday.

This will entail a phased approach, with water, ventilation and drainage systems prioritised, informing when the £150m hospital in Little France can finally be opened.

NSS will also review current and recently completed major NHS capital projects and to check all necessary standards have been met.

The health secretary has also escalated NHS Lothian to level three in its "NHS Board Performance Escalation Framework" - the system by which the government monitors if health boards are meeting the expected standards.

It comes after Freeman revealed she had overruled NHS Lothian in her decision to indefinitely delay the launch of the new hospital, which had been due to open on July 4.

Announcing the new measures, she said: "I understand that this is a disappointing and worrying time for parents and carers of patients who have appointments at the new children's hospital.

"However, safe, effective and high quality clinical services continue to be delivered from the existing site in Sciennes.

"The work carried out by NSS will give quality assurance on the water, ventilation and drainage systems and establish a timeframe for services to move safely to the new hospital.

"Infection prevention must always be embedded within the design, planning, construction and commissioning activities of all new and refurbished healthcare facilities, which is why I have also instructed NSS to review current and recently completed major NHS capital projects and provide assurances that the same standards have been adhered to."

Freeman added: "I recognise and appreciate that NHS Lothian staff have made considerable efforts both in the lead up to the planned move and following the delay.

"I have written to staff today to thank them for their hard work and for all that they are doing to help manage the situation, and for their excellent track record of providing high-quality patient care."

The Scottish Conservatives have called for a full Holyrood inquiry into the delay, branding it a "scandal".

Shadow health secretary Miles Briggs said: "All of these measures announced by the SNP government will only delay things further.

"This is a much-needed facility which was supposed to open in 2012 - the SNP has been in charge the whole time and must take final responsibility for the failure of this project.

"Families and staff will look at this announcement and wonder why these things weren't demanded of the construction firms from the outset.

"After all, the nationalists have had seven years of delays in which they could have ensured these boxes were ticked.

"The only way to establish the extent of what has gone wrong, why it has happened, and how we can ensure it's not repeated, it to have a full Scottish Parliament inquiry.

"It's the very least patients, their loved ones and the hardworking staff deserve."

Scottish Labour's health spokeswoman Monica Lennon said: "Patient and staff safety comes first but the lack of clarity over when the new Edinburgh Sick Kids hospital will be opened is completely unacceptable.

"Patients and staff who were due to move into the new building this month have been left in limbo, and Jeane Freeman hasn't even indicated if the new hospital will be safe for use this year.

"Serious safety concerns about the condition of the building should have been raised well in advance of its opening, so it's beyond belief that patients and staff find themselves in this situation.

"Jeane Freeman must get a grip on this latest NHS scandal and provide answers on how this was able to happen in the first place."