The government on Wednesday said it won't rule out the idea of setting up a "wealth fund" modeled on the Singapore government's Temasek, to invest in projects linked to the Greater Bay Area and the Northern Metropolis.

The idea came from New People's Party chairwoman Regina Ip, who called on the authorities to inject revenue generated by the three cross harbour tunnels into the new proposed fund after authorities take back ownership of the Western Harbour Crossing next year.

Financial services minister Christopher Hui said in response that officials are looking at different financing options for projects such as the Northern Metropolis.

"There's a good chance we'll have a cocktail therapy, in other words a composite plan. Because we have to look at the commercial viability, the possibility of introducing private participation and so on," he told lawmakers at a council meeting.

"There are many options, and the option you mentioned is one that we could consider, too."

Hui noted that toll fees generally go into the government's general account, which can be injected into the Future Fund under the Exchange Fund.

Meanwhile, two Election Committee sector lawmakers, Wendy Hong and Carmen Kan, called on the government to split the Future Fund from the Exchange Fund, as the latter is legally restricted from making "high-risk" investments.

They said a split would allow for a more diversified investment portfolio.

Hui said in response that there's already similar diversification, and the government's financial resources are not only used to seek monetary returns, but also consolidate to Hong Kong's status as a financial and trade hub in a strategic manner.