How many signatures are required to start the formal decision making stage of a direct democracy mechanism?

Citizens Initiated Referenda Act 1993

( Enacted on 28 September 1993)

http://www.legislation.govt.nz/act/public/1993/0101/latest/DLM317193.html?search=ts_act%40bill%40regulation%40deemedreg_citizens_resel_25_h&p=1

Article 18(2).

Subject to the provisions of this Act, an indicative referendum petition shall be certified correct by the Clerk of the House of Representatives if he or she is satisfied, in accordance with section 19, that the petition has, after the date on which the promoter received the written notice required by section 13(1)(a), been signed by not less than 10% of the eligible electors.