Is there a legally mandated filing fee and/or deposit?

Electoral Act 1989 (withappropriate reference to Electoral Amendment Act 2010), PART III - ELECTIONS, 17,p. 12

17.Recounts

(5) Anycandidate demanding a recount

shall pay, inadvance, to the Supervisor, a fee of $300 which shall not be refunded unless —

(a) thedifference between the original count and the recount exceeds

50 votes or 5%of the total votes cast in that district, whichever is

less; or

(b) as a resultof the recount, a different candidate is elected; or

(c) theSupervisor, in announcing his decision on the recount, certifies

that in hisopinion the demand for a recount was reasonable

http://legislation.to/Tonga/DATA/PRIN/1989-022/ElectoralAct1989.pdf

http://tongaelections.com/images/stories/TECdocuments/ENG/ElectoralAct/electoralamendmentact2010.pdf