Hundreds of evangelical pastors in Kenya are lobbying US President Barack Obama not to use his visit to press for the "gay agenda".

The 700 pastors are led by Bishop Mark Kariuki, head of the Kenya Evangelical Alliance, which represents 38,000 churches and as many as 10 million Christians in Kenya.

President Obama's first visit to his own father's homeland begins tomorrow and already the capital Nairobi is hung with Stars and Stripes bunting and flags, and posters bearing the slogan "Welcome Home".

But besides reports of political turbulence below the celebratory surface as he prepares to address the Global Entrepreneurship Summit, the churches in this devoutly Christian and conservative country are staking out the ground against any suggestion at all of a pro-gay agenda.

Homosexual acts between men are illegal in Kenya as well as more than 30 other African countries, carrying a prison sentence of up to 14 years, or even 21 years in some circumstances. Surveys show the vast majority of Kenyans, more than nine in ten, oppose the gay rights agenda.

There have already been anti-gay protests in the streets of Nairobi, led by Bishop Kariuki, who led Christians in chants such as: "We want Obama, we want Michele, and we want a child. We do not want Obama and Obama, we do not want Michele and Michele. We want Obama and Michele and we want a child."

They also bore placards which stated: "We don't want gay activities in Kenya."

Bishop Kariuki said homosexuality was against divine principles and an attack on the family and called instead for "moral values" to be instilled in youth. "Most of the issues that are going on today that have to do with population control are issues that are against the family. Homosexuality, condoms to young children in school, in Genesis 1: 26, 27 and 28, God said that we should be fruitful and multiply."

He added: "So when Obama comes, we are asking him to respect the morals of Kenyans, to respect the faith of Kenyans, he is coming for a commercial visit, let him talk about the conference but he should not talk about gayness because he is a world leader and our young people will start thinking that is a way of life.

"We do not want him to come and talk on homosexuality in Kenya or push us to accepting that which is against our faith and culture.

"Let him talk about development, let him talk about cooperation, let him talk about the long-time relationship Kenya has had with America. But about our beliefs and culture– keep off."

He described it as an "abomination" against God. "Kenya is 82 percent Christian. So, as far as our conviction and our faith are concerned it is not a natural thing."

Kenya's deputy president William Ruto has also appealed to the Christian community to stand up against homosexuality.

Speaking at a church service in Ziwani, Ruto he said the practice was against Christianity and should therefore be shunned, because Kenya was a God-fearing nation with no room for same-sex marriage.