According to an inquiry made to Sri Lankan airlines customer service in March 2016 posted here
Dear Sir/Madam
Thank you for contacting SriLankan Airlines.
Refer below criteria to be met in order to be eligible for complimentary >transit hotel accommodation as requested.
We regret to inform you that we do not handle visa queries. Please visit >www.eta.gov.lk for more information if required.
- The transit time should be over 8 hours and less than 24 hours.
- The net fare paid should be over USD 180(exclusive of taxes) for one->way journeys and over USD 360(exclusive of taxes) for return tickets.
- The connecting flight must be on the first available connection.
- Pakistani passport Holders should obtain ETA.
- Hotel accommodation will only be provided in Colombo.
If you require further clarification, please contact our Call Center on >the numbers below.
Within Sri Lanka – 1979 | From UK – 330 808 0800 | From Singapore – 315 >805 80 | From Germany – 6990 732 333 | From France – 9751 81999 | From >Hong Kong – 819 800 79 | From Japan – 505 532 3229 | From Italy – 0689 >970 268 | From Malaysia – 321 683 615 | From Thailand – 600 035 642 | >From outside Sri Lanka – +94 11777 1979
According to other posts in the same thread they can help with the visa, however they recommend doing it online as it is a relatively fast and easy process.
Credit:stackoverflow.com‘