A poll of members by sector body Colleges Scotland found half the country's new regions are predicting future staff cuts.
Three out of the ten college regions that replied also said staffing issues would impact on their ability to deliver courses.
A report on the survey by Colleges Scotland for the Scottish Parliament's education committee said: "All respondents stated they had recently reduced staff numbers and five indicated they expect to reduce numbers further.
"Three indicated concerns on funding covering staff requirements to deliver their targets."
Last year, a report by Audit Scotland found colleges face an 11% reduction in public funding by 2014/15 - amounting to £62 million - with reducing staff numbers "likely to continue to be colleges' main way of delivering savings".
The Audit Scotland report went on to warn that cutting staff numbers risked the removal of the skills and experience required to maintain the quality of learning.
Government funding cuts between 2011 and 2012 have already removed £56m from the sector, with the loss of 800 full-time equivalent staff - most of them lecturers.
John Henderson, chief executive of Colleges Scotland, said: "Colleges are being expected to continue to deliver the same level of full-time equivalent student numbers with less money in real terms and with increasing costs.
"As teaching staff numbers fall, that's likely to lead to a significant change is how education is delivered. Colleges and the Scottish Funding Council need to closely monitor the impact to ensure the student experience can be maintained."
Larry Flanagan, general secretary of the Educational Institute of Scotland teaching union, said it was a "huge concern".
He said: "Our colleges have endured some of the deepest cuts anywhere within the education sector over the last few years, with the loss of thousands of jobs, a sharp decline in the number of student places, and cuts to the range of courses available."
Gordon Maloney, president of student body NUS Scotland, said: "If colleges feel they don't have the resources and staff to deliver on their targets then that's clearly an issue of funding. It would be entirely wrong if the experience of students suffered because staff are losing jobs."
However, the Scottish Government said there was "no escaping" the need for efficiencies following cuts to the Scottish budget from Westminster.
A spokeswoman said: "We have consistently provided additional investment beyond spending plans - to the tune of around £130m since the 2011 spending review, creating a budget floor of £522m in 2013/14.
"This makes clear the priority we attach to colleges who are now also fully focused on delivering courses that provide viable career options for young people."
The survey also found community provision had been cut by six of the regions that had responded.
Mr Henderson said the college sector would welcome any additional funding to increase places for adults.