The National University of Singapore (NUS) is offering more places for alumni to sit in on classes at their alma mater from January next year, after its first run was nearly 20 times oversubscribed.

NUS received more than 8,000 applications for its first batch of 404 places in 79 modules that started in August.

A spokesman said that in response to the positive demand, it will open more than 970 places across 85 modules from January.

The university's scheme, known as the Lifelong Learning Initiative, is aimed at encouraging alumni to learn and adapt even as working adults.

Most of the courses are at the postgraduate levels, but there are also undergraduate modules.

The initiative, in line with the national SkillsFuture movement to reshape how people approach jobs, skills and learning, allows NUS alumni to take up to two courses over three years, from August this year to July 2020.

Course fees typically range from $3,000 to $3,500 per module. But alumni will not have to pay a cent in the first year, although there will be a student service fee of $261.85 a semester for the next two years.

Alumni have the option of taking classes without a grade or taking them for credit, and will be able to apply for an official transcript after finishing a module.

Most of the applicants were young working adults or recent graduates, with 86 per cent of them aged 39 and under.

The business school attracted 28 per cent of the applications, while the computing and engineering modules each drew 20 per cent.

Ms Wong Shu Yan, 29, who graduated from NUS in 2012 with a degree in industrial and systems engineering, is now taking an engineering management module.

"We learn about product innovation - looking at market demand and users' needs, studying trends, the competitive advantage of businesses," she said, adding that it complements her work as a training specialist in a semiconductor company, where she develops technical training curricula for engineers.

Ms Genevieve Yeep, a co-founder of a cyber-security start-up, is currently taking a module in personal finance and private wealth management, with the aim of planning her finances better for retirement.

The 47-year-old, who graduated from NUS business school in 1992, feels "old and young at the same time", going back to school.

"When I got my degree, my classmates were not even born yet," she said, adding that the module has given her new confidence in financial literacy.

Applications for the next batch of modules are open until Nov 15.