A 35-year-old man in the northern Indian state of Haryana has confessed to killing his wife after she refused to have sex with him, reports say.

Sanjiv Kumar, a painter who lives in a village near Jyotisar town in the Kurukshetra district, strangled his 30-year-old wife Suman after she resisted his attempt to have sex, The Times of India reported on Friday (Nov 17).

Police officer Ramesh Jaglan told BBC that Sanjiv confessed to the crime after he was arrested.

Mr Jaglan said Sanjiv's wife "had been refusing sex for a while", and her refusal again on Tuesday "irritated him and he strangled her".

The couple had been married for more than 10 years and have two children.

India's rape laws specifically exclude married couples.

A separate challenge to the laws on marital rape is currently going through the Indian courts, even as India's top court ruled last month that sex with a minor amounts to rape even if the couple are married.

The government has said it opposes criminalising marital rape as this would damage the institution of marriage, AFP reported.

In 2015, 35,000 rape cases were registered in India, an increase of 40 per cent since 2012 when the fatal gang rape of a young woman on a bus in Delhi sparked a national outcry.

Marital-rape counsellor and lawyer Monica previously blamed India's deeply entrenched patriarchal culture and a lack of awareness of women's rights for widespread sexual violence against women.

"Men think that marriage is a licence for sex. They don't even realise they need to ask for consent," said Ms Monica, who uses one name and works for non-profit group Maitri.