The mutual, which lent £220m in 2012, plans to lend up to 18% less in 2013. At least £135m is expected to be lent through brokers.
Mitcham told Mortgage Solutions: “We are doing a lot more buy-to-let. It works in Cambridge not only because of the university but also because the town is growing so quickly.
“We would also look to continue getting people into housing either through shared ownership or as first-time buyers.”
In 2012, Cambridge accelerated lending for a fourth consecutive year and beat 2008 figures by £32.4m. In total, it completed 1,158 new mortgages.
Mitcham also questioned the complexity of government schemes such as Help to Buy designed to kick start the housing market.
He said: “At the moment in the industry there is an excess of schemes. In some ways the ideal they have got to give was time to innovate around Funding for Lending and give us more time for schemes. I have been in the industry for 20 years and I have never known so many schemes.
“The intention behind Help to Buy is good, but in reality how many people will buy into it? That is the test.”
A Cambridge Building Society spokeswoman said £180m was a conservative estimate: “This target demonstrates that we want to continue to grow the business in a steady and sustainable way and similarly to 2012, we will consider any market opportunities that arise in 2013.“