In the old time, good employer may help you by assuming maximum deduction so that you pay less monthly tax and then at year end you yourself pay the due amount.
However, in the new system, employers are required to assume basic deduction only while others not. So most of you may ended up paying more tax monthly.
What you need to do is to go to this site and calculate for yourself how much tax you should pay monthly. Print it out and show it to your employer to adjust the figure.
This basically means if you want to pay less tax, you need to plan early and meet the targets of what you plan ie.
RM 5,000 Take responsibility and proactiveness in your parent's health
RM 5,000 Take a MBA course etc. Deduct educational fee from it ( for kids originally )
RM 1,000 Learn more, buy more books
RM 3,000 Buy a new computer every 3 years
RM 300 Sport gears
RM 3,000 Save for kids education in SSPN
RM 3,000 Your own medical insurance