Bus Vannin says a recruitment is underway to employ more drivers after another weekend of disruption.
The company has been plagued by service cancellations over the last three weeks due to a shortage of staff with vacancies to be filled and long-term absentees.
Weekends have proved particularly problematic with not enough casual drivers able to fill in.
Bus Vannin had to cancel almost 20 services on Sunday due to staff shortages and sickness which included main routes between Douglas and Peel, Port Erin and Ramsey, with the morning particularly affected.
The company has warned that further disruption can be expected while the staff issues are addressed.
A spokesman said: ‘Bus Vannin would like to apologise to passengers for the 18 cancellations on Sunday but also thank the drivers and office staff who undertook 489 services over the weekend.
‘It has been well-publicised that there is a shortage of drivers at present - currently 10 full-time vacancies from a full establishment of 92 - ¬and a recruitment process is underway.’
The spokesman added that, despite the disruption, numbers were up last week by 5.3% from the same period last year which equates to 4,000 extra passengers.
The company previously explain what the problem which is around staffing the routes.
It said on social media: ‘The bus timetable needs drivers to work overtime, particularly at weekends. Bus Vannin can also ask its casual drivers to provide cover, but last weekend (September 7-8)it was not possible to fulfil all of the duties.
‘Overtime is optional and many staff have continued to work additional hours to support the service in recent weeks – from driving colleagues to office staff. A driver’s hours must also be kept within daily and weekly agreed limits for safety reasons.’
To find out about becoming a bus driver and how to apply for one of the vacant positions, visit gov.im/jobs