The Election Commission, which has already proposed e-ballot for NRI voters, also said that voting can be facilitated only after the amendment of the Representation of People Act, 1950. However, it's unclear when the law would be amended.
The top court has given Attorney General KK Venugopal two weeks to inform when the law is likely to be amended.
The provisions of the Act were earlier amended in February, 2011. But the rules required the NRIs to be present in their constituency on the day of voting which many said wasn't feasible.
Last week, while hearing petitions by two NRIs -- Nagender Chindam and Shamseer VP - seeking their voting rights, a bench comprising Chief Justice JS Khehar and Justice DY Chandrachud had asked Centre whether it was going to amend the election law or rules to enable voting by NRIs without them having to be physically present and gave it a week to respond.
There are nearly one million NRI voters across the globe and only 10,000 come here to vote, Mr Venugopal told the court.
In its bid to attract more eligible overseas Indians to register themselves as voters in the country, last year, the Election Commission had launched an online survey for NRIs to assess their level of awareness about the voting process and their preferred method of voting.
Former Chief Election Commissioner Nasim Zaidi had said the poll panel wanted to systematically address challenges that overseas citizens face so that interventions can be designed accordingly.
In e-ballot voting, a blank postal ballot paper is emailed to the voter, who has to fill it and mail it by post to their constituency.