The Egyptian government has stepped up a campaign to curb Muslim Brotherhood influence over mosques, saying it has licensed more than 17,000 state-approved clerics to give Friday sermons to stop places of worship falling "into the hands of extremists".

The military-backed authorities have been trying to bring mosques under tighter control since the army toppled Mohamed Mursi of the Islamist Muslim Brotherhood last July after mass protests against his rule.

All of the newly-approved clerics had been trained at Al-Azhar University, which is a respected centre of Sunni Islamic learning, and institutions run by the ministry of religious endowments, according to a statement issued by the prime minister's office on Thursday.

"That is to strengthen the ministry's supervision over all Egypt's mosques so that they do not fall into the hands of extremists and the unqualified" and to prevent mosques being used for "party or sectarian" purposes, it said.

Last September, the religious endowments minister said unlicensed clerics would be barred from delivering sermons at mosques - long a recruiting ground for Islamist parties.

The government statement said the ministry of religious endowments had taken "a big step" towards addressing a shortfall in "qualified preachers".

Around 12,000 preachers not approved by the state had been removed from service, the statement added, without giving a time frame. Last September, the minister of religious endowments said he aimed to bar 55,000 unlicensed clerics.

The government has cracked down hard on the Muslim Brotherhood, the political movement that propelled Mursi to power in a 2012 presidential election.

The government has declared the movement, Egypt's best organised party until last summer, a terrorist organisation.

The Brotherhood denies any involvement in a campaign of lethal attacks that have mostly targeted the security forces since Mursi was toppled. – Reuters