Dutch Muslims on Tuesday offered to guard three Coptic churches in the Netherlands which have been threatened on an Al-Qaeda-linked website after a New Year's Day bombing killed 21 Coptic Christians in Egypt.

The Dutch Muslim Council, the Council of Moroccan Mosques in the Netherlands and the Federation of Islamic Organisations "offer protection" to three Dutch Coptic churches which were among 50 in Egypt and Europe threatened on a list on an Al-Qaeda-linked website, they said in a statement.

The Dutch Islamic groups promised to ensure that "Muslims are ready to guard the three churches, in Amsterdam, Utrecht and Eindhoven, against the threat by Al-Qaeda".

The Netherlands counts some 6,000 Coptic Christians, seven Coptic churches and about a million Muslims.

The Dutch groups urged all Muslims to condemn the threat.

"It is up to us to do so because Al-Qaeda is claiming to act in the name of Islam. Christian Copts, us (Muslims), and all Dutch have the same enemy: the terrorists," the statement said.

"We can't sleep at the idea that Christian Copts may be attacked here, in the Netherlands."

Pastor Arsenious El Baramousy of the Amsterdam Coptic Church told AFP he would be meeting Muslim leaders later Tuesday. "I will accept their offer, which has made me very happy," he said, adding about 12 Coptic volunteers were already guarding the Amsterdam church and scrutinising all visitors.

The pastor said he had contacted the police "who are taking measures" ahead of the orthodox Christmas to be celebrated on Friday.

Utrecht police confirmed they had upped security around the city's Coptic church.

Egypt has been on high alert ahead of January 7, when the Coptic church celebrates Christmas, following the church bombing on Saturday that killed 21 people and injured 79.