The action highlights a shift in strategy among shareholders concerned about the impact of climate change from selling their shares in coal mining and power companies to pressuring banks and contractors involved in projects.
The letter being sent to the Vung Ang consortium on Thursday has been written by Nordea Asset Management's head of responsible investment Eric Pedersen, and backed by other investors including the Church of Sweden and Brunel Pension Partnership.
"Vung Ang 2 is fast becoming the prime exhibit in the case against companies taking on irresponsible transition risk on coal plants, not to mention the obvious conflict with the commitments of those same companies to align with the Paris agreement," Pedersen said in a statement on Wednesday.
Nordea said it holds shares worth nearly 400 million euros ($474 million) in the publicly listed members of the consortium building the project. Other members of the investor group did not outline their specific exposure.
The 1.2 gigawatt Vung Ang project, one of a number of coal power stations under construction in Southeast Asia, is being built to meet Vietnam's surging demand for power, with the support of the Japanese and Vietnamese governments.
The letter is being sent to all sponsors, financiers and contractors involved in the project, according to the statement.
They include Mitsubishi Corp, Korea Electric Power, Japan Bank for International Cooperation [JBIC.UL], Mizuho Financial Group, Mitsubishi UFJ Financial Group and Sumitomo Mitsui Financial Group.
The banks and companies within the consortium declined to comment when contacted by Reuters. Japanese banks have recently tightened lending criteria to coal projects.
(Reporting by Aaron Sheldrick; Additional reporting by Joyce Lee in Seoul; Editing by Jan Harvey)
By Aaron Sheldrick