MANILA, Philippines -- For lack of implementing rules and regulations (IRR), the law exempting minimum wage earners from the withholding tax and granting bigger exemptions to other fixed income earners remains unenforceable some two months after President Gloria Macapagal-Arroyo signed it.

Finance Secretary Margarito Teves said. Wednesday there is still a debate on when the law should take effect.

"They're still trying to resolve the effectivity date of the law…We'll see if we can have an update next week," Teves said after a hearing of the joint congressional committee on the comprehensive tax reform package.

Teves said the Bureau of Internal Revenue (BIR), which is working on the IRR, holds the view that higher exemptions should take effect in July, while the legislators and other sectors believe it should be for the entire year.

"As a general rule, we normally interpret laws to be prospective in character. But in the case of income tax, normally it's [a] full-year consideration," he said.

During the hearing, the legislators asked the finance department to look into the intent of the law, which is supposed to apply for the whole year.

Arroyo signed the law on June 17 and it was supposed to take effect 15 days after its publication in a newspaper of national circulation.

While the law allows minimum wage earners to take home as much as P750 a month, or from P33 to P35 a day, it also provides for an increase in the personal exemption of other taxpayers.

From the current P20,000 personal exemption for single taxpayers, P25,000 for head of family, and P32,000 for married individual, the law fixes the tax exemption at P50,000. The additional exemption for dependents will also increase from P8,000 to P25,000.

The law also provides that all holiday, night differential, hazard, and overtime pay be tax-exempt.

In discussions while the law was being crafted, senators said the measure would allow an employee earning P455 per day or P10,010 per month to have an additional take-home pay of P472.59 per month or P5,671.02 per year if unmarried; P678.50 per month or P8,142.04 per year as head of the family; and P580.92 per month or P6,971.02 per year for married workers with four children.

An employee earning P683 per day or P15,026 per month would have an additional take-home pay of P545.26 per month or P6,543.10 per year if unmarried; P1,307.18 per month or P15,686.20 per year as head of the family; and P1,190.52 per month or P14,286.20 per year for married workers with four children.