Loss-making APL has fallen steadily behind rivals able to invest in larger and more economic containerships in recent years, while Temasek has sold off its profitable assets. APL Logistics went to Japanese forwarding group Kinetsu World Express for $1.2bn in May.

Rumours this year have already linked APL to possible acquisitions by Hong Kong-based rival OOCL and Germany’s Hapag-Lloyd - but there has been little solid evidence to back up the speculation.

Temasek, which never comments about market speculation, has over many years considered NOL a strategic asset, but that thinking could have changed as Singapore’s huge container port is able to survive without a national carrier, and APL shows little sign of being profitable.

NOL also declined to comment about the latest story which appeared in the Wall Street Journal.

NOL’s market capitalisation is currently about $1.7bn but the poor economics of container markets, which are overtonnaged and in receipt of a steady stream of 20,000-teu megaships that are worsening conditions, mean there may be little appetite among potential buyers to pick up more capacity – unless it comes cheap.

Including debt the company’s value could be set as high as $$8bn ($5.9bn), according to market data. NOL cut its first quarter net loss to $11m, compared to $98m a year ago, but market conditions have worsened again since then. The group has rung up a loss of $1.2bn over the past four years.