The boss of Translink has rejected claims of running "ghost buses" with hardly any passengers on them as he revealed that coronavirus is costing the company £10m a month in lost revenue.
Chris Conway said that he took "exception" to the implication that some services are unnecessary, insisting that a public transport network cannot be run without a timetable.
And he said Northern Ireland's public service provider desperately needs a further £100m from Government this financial year to cope with the pandemic.
He added that Translink's stringent health and safety measures meant that fewer than 10 of the company's 4,000 employees have tested positive for Covid-19.
The chief executive - who was appointed five years ago - made the comments during an interview with the Belfast Telegraph on the financial impact of the virus on the company, which is hugely subsidised by the public purse.
"I take exception to talk of ghost buses," Mr Conway said, when asked if it is cost effective to run services with fewer passengers. "You have to run a public transport network to a timetable. We are running an essential service. A quarter of the population in Northern Ireland doesn't have access to a car.
"Certainly there will be times of the day when you'll have less people using us, and people may have noticed buses that have very few passengers on them, or occasionally no passengers on them, but that's the virtue of how you run a timetable."
He added: "The fact is, the network itself still carried, relatively speaking, a high number of passengers that needed essential travel and we think it's important to provide that service."
Mr Conway, who replaced David Strahan in the £156,000-a-year post on May 22, 2015, said Translink has introduced a range of "network-wide changes" to improve safety for staff and service users.
"Our timetable was the first thing; we've always maintained a level of timetable that will allow people to socially distance on our vehicles," he said.
"We've also put in additional measures so that people didn't have to use change.
"We've increased the number of tickets you can buy on your phone app, we've got Smartlink cards and we have a 'no change' policy so if you do only have cash we've told people that the change will go to charity."
Mr Conway said there are "lots of measures for social distancing in place".
"We've got lots of signage, we've got hand sanitisers in all our stations, we've put up Perspex screens in buses and coaches," he said. "We've introduced PPE for conductors on trains; they have access to face visors and face masks.
"We've put screens around our ticket lines and ticket desks and we've put in place a whole process around cleaning vehicles - hygiene cleans during the night and day and deep cleans on a regular basis as well."
While Mr Conway would not call for compulsory face masks, preferring to follow the Health Minister's guidance, he said Translink has "face coverings available for all of our staff".
He added: "I use the bus every day when I'm going into work and I use a face covering and we're recommending that people do that."
In Northern Ireland, Translink has reported no fatalities - unlike London, where 33 bus workers, including 29 drivers, died from Covid-19.
"We've had no deaths and under 10 cases out of 4,000 employees," Mr Conway said.
"And I think that is evidence of all the hard work we've put into this and the fact that we've maintained a certain level of capacity to allow people to socially distance."
Translink has been using up cash reserves since its annual subsidy was cut by £13m in 2015/16 and, even before the pandemic, was bracing itself for severe financial straits this year, having run up a deficit of £20m.
Mr Conway said the expected extra cost of the pandemic to Translink is £100m.
He added: "What we've said is ... the budget has already been allocated to us, which was mostly for operating public service obligation services and things like that, we've said that approximately an additional £100m will be required to continue to run this service for this financial year."
"In terms of lost revenue, it's around £10m a month."
Mr Conway said furloughing staff has never been a viable option for Translink.
"During the month of April, which would've been the eye of the crisis, we were still carrying 80,000 passenger journeys a week, including essential workers and people who had no access to cars," he said.
"Furloughing would not have been appropriate in that scenario because it didn't fit with the government guidance and it didn't fit with what we were trying to do for Northern Ireland, which was to run an essential service."