As Muslims begin their holiest time of the year, Ramadan, Christians around the world will be praying for them.

Open Doors is asking Christians to pray for the world's 1.6 billion Muslims over the next 30 days as they fast and seek true answers from God.

"Why not take the opportunity this year to share the love and pray they'll hear His voice?" the organisation asks.

Its resource includes prayer points for new believers from Muslim backgrounds and facts about the Muslim world.

There is also a "Just for Kids" version that includes quizzes, games and suggestions for prayers that are suitable for children. 

Ramadan falls in the ninth month of the Islamic calendar and is an especially holy time of fasting and prayer.  It is also important because the Koran was first revealed to the Prophet Muhammad during this month.  

Muslims are required to fast during the hours of daylight and it is tradition to eat a meal before dawn, Suhour, to start the day's fasting and end it with another meal just after sunset, the Iftar.

Open Doors is also asking for prayers for Christians living in contexts of persecution in Muslim-dominated countries.

"Not only is it a time to pray that these Christians will stand strong [during] Ramadan, but also that Muslims will be given an opportunity to hear the Gospel," the organisation said.