The church led by American pastor and author Tim Keller is launching a new seminary in its hometown of New York, in partnership with a conservative Bible College, to prepare church leaders for ministry in cities around the world.

Redeemer Presbyterian Church, which Keller founded in 2001, is joining with the Reformed Theological Seminary to offer a campus in New York. The new course will launch next year.

Bible colleges in the US are struggling with reduced revenues following the financial crisis, but the RTS, which started in Jackson, Mississippi, is expanding across America in various locations, as well as offering a 'virtual campus' online.

Keller's church has been involved in planting more than 300 churches in 45 cities, including Scotland, Liverpool and London. It is now part of the 'Redeemer City to City' umbrella group.

Keller has become well known in Christian circles due to his prolific writing career, which includes the titles The Reason for God and The Meaning of Marriage. He also took part in launching the Gospel Coalition, a group of Christians who come from a conservative theological perspective.

The pastor said in a statement that the new partnership will train church leaders specifically for an urban setting. "The Bible calls us to take the gospel to the nations, but the nations of the world are pouring into the cities on a history-changing scale," Keller said.

"This massive migration is both a significant opportunity and challenge. Even in parts of the world where Christianity is growing rapidly, the national churches have difficulty reaching their own greatest urban areas. We are thankful for this new partnership with RTS, through which we hope to prepare leaders for ministry in New York and the other great global cities of the world," he added.

The new partnership will include two years of Biblical studies, and then one year of practical experience in one of the Redeemer churches.

"RTS is thrilled to collaborate with Redeemer City to City and with Tim Keller to prepare a new generation of ministry leaders and establish an RTS extension in New York," said Dr Ligon Duncan, who heads the theological seminary.

"I have known and admired Dr. Keller for many years. I count him as a friend and I am deeply grateful for his ministry and vision for planting churches in New York and in other major metropolitan centers around the world. The board of RTS and I are pleased to partner with CTC to offer a rigorous program of graduate theological study in NYC."