"Tomorrow at the UN Ocean Conference in France, I'll announce the government's plans to ban bottom trawling across 41 protected areas of English seas spanning 30,000 square kilometres," or 11,600 square miles, environment minister Steve Reed wrote in the Observer newspaper on Sunday.

There are currently 181 Marine Protected Areas, covering 93,000 square kilometres (km2), or 40 percent of English waters.

Around 18,000 km2 of those waters are currently protected, a number that would rise to 48,000 km2 under the government's plans.

"This will help conserve vulnerable underwater life and allow the seabed to recover from the damage caused by this destructive practice," Reed wrote.

He said bottom trawling, in which heavy nets are pulled along the seabed, was "destroying the most vulnerable areas of our oceans".

"Our seas will be irreversibly damaged if we don't act urgently," he wrote.

World leaders started gathering on the French Riviera on Sunday ahead of the summit to tackle a deepening crisis in the oceans driven by overfishing, climate change and pollution.

The United Nations says oceans face an "emergency" and the leaders gathering in Nice will be under pressure to commit money and stronger protections for the seas and the people who depend on them.