The Malaysian ringgit has tumbled to a new low since it was unpegged from its fixed rate of 3.80 in 2005.

As of 4.30pm, the ringgit was valued at 3.9083 to the US dollar.

The ringgit has been falling at an accelerated rate in recent months from around RM3.20 to US$1 a year ago.

Among the factors attributed for the weak currency include falling global oil prices which has impacted the country's revenue as well as political instability.

Prime Minister Najib Abdul Razak has been struggling to defend his position amid allegations that RM2.6 billion was deposited into his private bank accounts.

Domestic manufacturing have also been hit amid rising cost following the introduction of the Goods and Services Tax (GST) in April.

Malaysia's manufacturing sector continues to worsen in July to the second-weakest in over two-and-a-half years, according to the latest survey from the Nikkei and Markit Economics released on Monday.

According to the Nikkei manufacturing purchasing managers' index, Malaysia's score rose slightly from 47.6 to 47.7.

Any reading under 50 indicates a contraction in activity.

It attributed the further decline in July to "poor demand and challenging economic conditions".