Although none of the $1b announced in the Budget was going into coastal shipping, the Government has an announcement planned in this area.
"We're working on it, and we'll get back to you on that," Twyford said.
Deputy Prime Minister Winston Peters also signalled the Government's plans for spending more money on the new maritime and roading initiatives.
He said the money spent on KiwiRail was to help get "these leviathans" – an apparent reference to trucks – off the road and give ratepayers and taxpayers a chance to build and maintain roads at an affordable level.
He said every other country in the world apart from New Zealand was doing this.
Asked if that meant the Government would be investing further into roads, Peters said: "You're going to see balanced investment; in maritime, on rail and on roads."
"All three modes of transport – they have always had a place in New Zealand, and they've got a place in our future."
Peters and Twyford, along with Finance Minister Grant Robertson and Regional Economic Development Minister Shane Jones, this morning announced a few further details of the $1b KiwiRail spend.
By 2023, there would be 100 new locomotives and 900 new container wagons in operation.
The new funding would be used to replace some of the older trains, which, according to Peters, were "tired and worn-out".
More details of the Government's rail plans will be announced in the coming months, Twyford said.
Robertson added that the $1b spend was only the beginning of how New Zealand's rail system is funded.
"I don't believe there is anything within our budget on the economic side that emphasises wellbeing more than rail."