A total of 403 people have died in Wales from the coronavirus after a further 19 people died, but Public Health Wales said the number is likely to be higher.
238 new cases also have tested positive for Novel Coronavirus, bringing the total number of confirmed cases to 5,848.
Public Health Wales (PHW), said it is working with Deloitte to integrate reporting systems from the testing facility at Cardiff Stadium so they can be included in the data.
New ONS stats revealed the number of people to have died in England and Wales after contracting coronavirus could be significantly higher than the figure reported by the government.
Care homes are an area of growing concern after 13 residents at one facility died following an outbreak.
Around a third of care homes in Wales have a suspected or confirmed case of coronavirus, the health minister confirmed.
In Tuesday's daily Welsh Government press conference, Vaughan Gething said 75 homes have a confirmed Covid-19 case, and 217 have suspected cases. He also said he expects that number "to increase."
Two more healthcare workers in Wales died over the Easter weekend, after contracting the virus.
Donna Campbell worked at one of Velindre's cancer centres before passing away in the University Hospital of Wales in Cardiff on Friday. On Saturday it was confirmed that nurse Gareth Roberts had died in the Prince Charles Hospital in Merthyr Tydfil.