Abdullah Ahmad Badawi said on a visit to relief centres: "They are going through a lot of hardship. What matters most is that aid be given to the victims as fast as possible."
The government has set aside $100m - three times the previous estimate - to repair roads, bridges and infrastructure in affected areas.
Each displaced family is to receive up to $255, along with mops and pails for cleaning up.
Güncelleme Tarihi: 20 Eylül 2018, 18:16
The muddy waters up to three metres high have killed at least 17 people in submerged towns and villages since mid December.
Local media have also reported two deaths caused by water-borne diseases.
Last week, torrential rains sparked a second wave of floods in three weeks, the worst Johor has ever seen, with hundreds of cases of diarrhoea being reported in the overcrowded relief centres.
About 68,000 people still remain at about 200 centres throughout the state, Johor police said on Thursday.
The New Straits Times daily said the government has promised $57 for victims of the first wave of floods and another $57 if they were caught in the second wave.
Each family will get an additional $140 when they return home after the waters recede.
"All victims will be helped fairly and distribution of financial aid must be done as fast as possible," the newspaper quoted Abdullah as saying.
Officials have said the severity of the floods showed that storm drains needed to be widened.
Samy Vellu, the works minister, said the rebuilding of the infrastructure "would be done within six months' time, if the weather permits".