Anti-persecution charity Christian Solidarity Worldwide (CSW) is concerned about the severity of these five charges.
Both pastors, Revd Yat Michael and Revd Peter Reith, from the Presbyterian Evangelical Church, have been accused of undermining the constitutional system of the Sudanese Penal Code; waging war against the state; disclosure and receipt of official information or documents; arousing feelings of discontent among regular forces; breach of public peace; and offences relating to insulting religious beliefs.
The Africa Advocacy Officer at CSW, who can't be named for security reasons, told Premier the men have been accused of two very serious charges: "Waging war against the state and undermining the constitution - both these charges carry the death penalty or life imprisonment in the event of a guilty verdict.
Revd Yat Michael's been detained since December last year and Revd Peter Reith since January 2015. They were first brought before Khartoum Bahri Criminal Court in Khartoum, Sudan on 4 May.
The Africa Advocacy Officer at CSW told Premier they were defiant just days before their arrest: "Revd Michael gave an address on Sunday and encouraged the church to continue standing firm against the trials that they were facing.
"And moments after this he was arrested by national intelligence and security services who said they took offence by the words he gave to the congregation.
"For us, we see a very clear link between the pastors' arrest and the church in Sudan.
"The two pastors had been held in incommunicado detention - that means they weren't able to contact their families, and their families weren't able to meet with them.
"They weren't even given access to a lawyer until 1 March this year."
CSW said the severe charges levelled against them are the latest development in a series of repressive official actions targeting Christians in Sudan, a predominately Muslim country.
Listen to Premier's Hannah Tooley interview the Africa Advocacy Officer at Christian Solidarity Worldwide, here:
