Aneurin Bevan University Health Board says it will now be taking legal proceedings to take back possession of the car park at Royal Gwent Hospital in Newport.
It says it had asked a group of travellers from France, who have parked caravans in a section of the staff car park, to leave by 4pm today - but they are still on site.
More top news
Carwyn Jones speaks to our Political Editor Adrian Masters in the final part of our pre-election series on ITV Cymru Wales.
Alexandra Lodge has been to Aberconwy, where Plaid Cymru, the Conservatives and Labour are all hoping to claim victory.
Cloudy skies to start the day, and rather windy with prolonged rainfall during the morning which will be heavy at times.