With power cuts being applied across the South Island by June 1956, the Minister of Works requested the contractors to concentrate all resources on work that would bring forward lake filling as far as possible. To encourage the workforce, the government offered a bonus of £2 per week plus £1 per day if the lake was filled before 19 August. At midnight on the 21 July 1956, lake filling began and the lake level commenced rising at an average of an hour.