O'Neill will bring his squad together for an eight day training camp which will include a friendly against Qatar in Crewe and a training match against the Republic of Ireland in Dublin.
The players will then have a short break before getting together again for a training camp ahead of the qualifier against Romania on June 13.
"The players will be very well prepared for the qualifier. They know the expectations in terms of maintaining their own fitness and I have no concerns about that. We have a really good bunch of lads, good professionals, easy to work with and they will look forward to the game against Romania."