"It is just as important to keeping us connected and functioning as a region as the work others involved with the provision of essential services are doing at this incredibly difficult time," he said.
Graham also reminded people to travel only when essential.
"The key message is if you do not need to travel you should stay at home," he said.
"The regional council will not tolerate any abuse of this service by non-essential free riders, and if we get evidence this is happening, that could put this vital service in jeopardy."
Until further notice, the regional council will continue to operate the Saturday timetable services, plus routes 10, 11, 16A, 16B and 17 on weekdays.
Williams also said that the regional council was acutely aware of the need to ensure bus driver safety.
"Firstly, these bus services are available only to people working in essential services, such as hospital staff and healthcare workers, or people getting to supermarkets, health care facilities and pharmacies," he said.
"Screens are in place to keep the necessary distance between passengers and the drivers."
Williams added: "Anyone boarding a bus should keep a note on their phone or in their diary or notebook of the date, time and trip travelled on or complete a form online at www.gobay.co.nz."