They will be asked upon admission to give their signed consent to grant hospitals permission to check up on their income.

Details of how much they earn, however, will not be disclosed to counter staff, who will know only the subsidy band into which patients fall.

A Health Ministry spokesman said hospital admission systems will be linked to the Central Provident Fund Board and to the Inland Revenue Authority of Singapore so the subsidy level can be calculated and bill estimates presented to patients.

Patients may refuse to have their incomes checked. But this will mean they will automatically get the smallest subsidy - 50 per cent for treatment in a B2 ward and 65 per cent in a C-class ward.

Up till Wednesday, B2 and C-class patients got their respective flat subsidy rates. From Thursday, patients in these two ward classes will fall into one of 16 subsidy levels.

Read the full story in Thursday's edition of The Straits Times.