In a statement issued by the delegation, led by the presiding bishop of the SA Methodist Church, the group said it was "traumatised" by what it saw there.
"We did not expect the extent to which Israel violates international laws to oppress the Palestinian people."
The delegates described Palestinian East Jerusalem and the Israeli-Occupied West Bank as reminiscent of "an apartheid ambush".
"Our visit was undertaken in direct response to the Palestinian Christians' invitation to come and see for ourselves what their circumstances are."
The Christian leaders arrived in the area last Sunday.
"We affirm the right to security, self-determination and dignity for both Palestinians and Israelis."
Coming from South Africa, the delegates felt it their duty to speak up for, and stand with those suffering under oppression.
"We do not want to necessarily side against the Israelis, but we do want to uphold international law and fight against any form of injustice."
Siwa was accompanied by 11 others, including secretary general of The Evangelical Alliance of SA Reverend Moss Nthla and President of the Anglican Youth of Southern Africa Nonhlanhla Shezi.