Investment promotion minister Sarath Amunugama said at the signing ceremony that Bharti had faced difficulties in getting approvals for its towers from local authorities and sharing towers with other operators.
Company officials present at the ceremony declined to give specific reasons for the delayed launch.
Amali Nanayakkara, chief executive of Bharti Airtel Lanka, said they want to launch their mobile phone operation only when they were sure they had the right infrastructure to give customers the desired quality of service.
She said they had not faced any rejections from the authorities or rival operators.
"Sharing towers is a new concept for existing operators. It also depends on whether space is available and their own expansion plans."
She said the firm was willing to share the