At least 31 people have been injured following clashes between Muslims and Coptic Christians in northern Egypt.

A security official said that at least 20 people from both sides were arrested for their involvement in Friday's unrest, which included the lighting of fires in the Mersa Matrouh province.

"Security was able to control fires that erupted in three homes and two cars," Ahmed Hussein, the governor of Mersa Matrouh, told state television on Saturday.

Fighting was said to have begun when Muslim residents threw stones at Christian construction workers they believed were building a church.

The construction workers said that they were rather building a wall for a hospice.

"A heavy security presence was deployed to the town and remained overnight to make sure there are no more clashes," the official said.

Copts, who make up 10 per cent of Egypt's 80 million population, complain of frequent discrimination.

In January, armed men fired on worshippers leaving a Christmas Eve service in the southern town of Nagaa Hammadi, killing six Copts and one Muslim policeman.

Three people are being prosecuted over the attacks.