India's top court has upheld a law which criminalizes gay sex, in a ruling seen as a major blow to gay rights.

The Supreme Court ruling reverses a landmark 2009 Delhi High Court order which had decriminalized homosexual acts.

“It is up to parliament to legislate on this issue,” Justice GS Singhvi, the head of the two-judge Supreme Court bench, said in Wednesday’s ruling, which came on his last day before retiring.

According to Section 377, a 153-year-old colonial law, a same-sex relationship is an "unnatural offence" and punishable by a 10-year jail term.

Several political, social and religious groups had petitioned the Supreme Court to have the law reinstated in the wake of the 2009 court ruling.