French presidential candidate Emmanuel Macron is hunting for votes in rural areas of France where his far-right opponent, Marine Le Pen, has made recent inroads.

Ms Le Pen has sought to appeal to people who feel left behind, with difficult access to public services, mobile phone connections and other modern conveniences.

However, in a radio interview on Saturday, the centrist Macron said that, if elected, his government would intervene directly if mobile operators fail within 18 months to install high-speed fibre optic and phone networks "everywhere".

"I will give them 18 months to finish these deployments, be it fibre optic or 3G/4G," he said.

"If at the end of these 18 months, they have not fulfilled their responsibility, the state will substitute itself in their place to do this, within the framework of the investment plan I've decided."