The Maritime and Port Authority of Singapore (MPA) will be led by a new chief executive with effect from Jan 1 next year.
Mr Andrew Tan, the former chief executive of the National Environment Agency (NEA), will replace Mr Lam Yi Young, who has led MPA since May 1, 2009.
Mr Tan, 46, was CEO of NEA from January 2009 to June this year. He is currently the Deputy Secretary (Special Duties) in the Ministry of Transport and holds a concurrent appointment as Fellow in the Civil Service College.
From 2002 to 2004, Mr Tan was principal private secretary to then-Senior Minister Lee Kuan Yew, and subsequently held senior appointments in the Foreign Affairs Ministry and Environment and Water Resources Ministry before joining NEA.
Mr Lam, 41, is leaving MPA to join another ministry.
The Transport Ministry said on Monday that it appreciates Mr Lam's "significant contributions" in his four and a half years as MPA's chief.
Mr Lam spearheaded Singapore's development as a vibrant international maritime centre during his tenure at MPA, the Ministry said.
It also noted that Mr Lam steered MPA towards greater public outreach and education through activities such as the Singapore Maritime Week.
The Ministry added that since 2009, Singapore has maintained its standing as the world's busiest port in terms of annual vessel arrival tonnage.
A spokesperson for the Transport Ministry told The Straits Times that Mr Lam will be posted to another ministry as part of his Administrative Service tour, although it did not provide any further details.