The vast majority of the HSE's servers have been decrypted after the damaging cyberattack, which is likely to cost the health service half a billion euro.
It has now decrypted 80% of its servers taken out of action by a ransomware cyberattack in May, though the road back to full capacity is still likely to be a long one, senior staff have said.
The HSE also says that 79% of its computer devices like laptops and tablets are now also functioning properly once again.
Speaking onthis morning, HSE chief operations Officer, Anne O’Connor said that there is still a significant amount of work to be done before the service fully recovers from the attack.
“Our email system, whilst it is back, it’s not working in the way that it was yet,” she said.
“Many of our systems are back, but they’re not necessarily working as they were before, or they’re not interfacing with other systems in the same way.”
Ms O’Connor said the HSE and IT experts working to decrypt devices and restore functionality were now facing into “a slower phase” where thins “wold take a bit longer.”
“Some of the issues we’re trying to address are tricky, technical issues, so while the majority are back, we expect it to be a number of weeks before we have all of our systems back.”
Late last month, HSE boss Paul Reid stated told an Oireachtas Committee that the overall cost of the cyberattack to the health service could exceed half a billion euro.
Mr Reid said immediate costs would amount to more than €100m, but that this would increase significantly following consultation with specialists, international experts, and the introduction of more up-to-date software and security systems across the service.
“There are particular costs in relation to capital costs, which would be the replacement of a number of devices across the networks. There is also capital costs in upgrading key systems to have them at a higher standard," he said.
“Third-party costs which relate to a number of technical expertise that we have engaged from a range of specialist providers.
“There are costs we will incur in the future, and we need to put in place a security operation centre to monitor our network on a more comprehensive basis.”
Mr Reid said the service had previously invested €82 million in malware protection but, that the HSE did have "an old legacy network."
"It needs investment for protection, it needs investment for security and protection of data, and we will have many lessons learned from this in reports we will get," he added.