Connacht and Ulster can return to full rugby training on Monday after testing at both provinces earlier this week detected no cases of Covid-19.
Leinster and Munster have both been back since Monday last, observing strict protocols around gym equipment, training in 'pods' of seven players and without access to dressing-rooms, kitchen areas or video analysis rooms.
Players and staff have their temperature checked daily with a contactless scanner to ensure it is below 37.5C.
It has been almost four months since any of the provinces played a match and the Pro14 season has been abridged, with just two rounds of local derbies in each country now remaining.
Leinster and Munster will face each other at the Aviva Stadium in their first game back on 22 August with Ulster and Connacht squaring off in Dublin on the same weekend. Leinster conclude their regular season campaign against Ulster a week later when Munster take on Connacht, again at the Aviva.
The top two in each Conference will then proceed to semi-finals on 5 September with the final on 12 September at a yet to be confirmed venue.
Leinster are already guaranteed to top Conference A while Ulster (A), Munster (B) and Edinburgh (B) are likely to take the remaining three slots.
Confirmation from @IrishRugby that this week's PCR testing has produced 0️⃣ positive results.— Connacht Rugby (@connachtrugby) June 27, 2020
Our pro players and staff can now commence pre-season training on Monday 💪🟢#ReturnToRugby
More: https://t.co/LIoNHP35PO pic.twitter.com/gmIVUtvYCL
A statement from the Irish Rugby Football Union today said "The IRFU can confirm that the PCR testing of players and staff at Connacht and Ulster produced zero positive results.118 players and staff were tested on Wednesday 24 June in Connacht and Ulster.
"The PCR testing was carried out by Cork based company Advanced Medical Services on behalf of the IRFU.
"The staff and players have been cleared to access their respective High Performance Centres from Monday 29 June."
From the 29th June all four provincial senior squads will be back training in modified groups.
To date there have been 258 tests conducted across the professional player and staff group and zero positive tests reported.
IRFU Medical Director Rod McLoughlin commented, "The first phase of PCR testing has been successfully completed.The players and staff now enter a period of daily medical screening and assessment.The second phase of testing will take place as players return to contact."