Tonga's electoral officials are appealing for voters to register promptly under the new political system to apply for the poll in November.
Radio Tonga reports there are concerns after a poor turnout for registration in two major electorates on Tongatapu, Kolomotu'a and Kolofo'ou.
A senior electoral officer, Vake Blake, estimates that in the first week of registration around seven thousand people have ensured they're on the roll.
But she's expecting an improved turnout from now, after appeals made on television and radio.
In order to register, people are asked to provide identification, such as a birth certificate, passport or driving licence, though those unable to provide any of these documents will be helped by registration officers.
The voting population on Tongatapu is put at just over 37 thousand, with seven thousand in Vava'u, three and a half thousand in Ha'apai, two and a half thousand in Eua and less than 800 in the Niuas.
