The Competition Commission of India (CCI) said the deal would not have any adverse impact on the competition scenario.
In its order on December 26, CCI noted that operations of PNB and MetLife India are not similar or identical.
"Although PNB provides services to MetLife India as a distribution agent, the share of MetLife India in the business of life insurance is relatively insignificant and is not likely to raise any adverse effect on competition in India," CCI said.
In 2011, PNB had announced picking up of 30 per cent stake or about 60.38 crore shares in MetLife India for an undisclosed amount.
Besides, the two entities had reached an agreement following which PNB is acting as an agent of MetLife India for the distribution of its insurance products.
MetLife India is a joint venture between MetLife International (an affiliate of US-based MetLife Inc) and group of Indian investors.
Both PNB and MetLife India had approached the fair trade regulator for approval on December 7, 2012.