AHMEDABAD, India (AFP) - The Indian state of Gujarat wants to make it mandatory for anyone standing for public office to have a toilet at home, in order to discourage the common practice of open defecation.

A Bill passed by the Gujarat state assembly late on Monday also requires all existing government members to declare within six months whether they have a toilet at home, or face disqualification.

"Curbing open defecation is vital from the point of view of creating hygienic conditions and cleanliness and preventing water contamination," the state government said.

Gujarat is the home state of India's new Prime Minister Narendra Modi, who has said every household should have a toilet within four years to prevent the spread of disease caused by open defecation.

The Gujarat government said it was already providing financial incentives to local people to build toilets at home, but wanted to set an example.

A recent report by the UN children's fund Unicef estimates almost 594 million - or nearly 50 per cent of India's population - defecate in the open.

Being forced to squat outside at night also exposes some 300 million women and girls to potential harassment and assault.

The issue was highlighted in May when two girls, aged 12 and 14, were attacked as they went into the fields to relieve themselves. Police are investigating if they were gang-raped before being lynched.

The Bill will now go to the governor for final approval.