Adani says it will soon start work on a rail link for its Carmichael coal mine, despite needing billions in finance.

Adani Mining chief Jeyakumar Janakaraj says the company is “confident and committed” to delivering its first coal shipment in March 2020, and that pre-construction works at Carmichael and its 388km rail corridor to its Abbot Point port are “well advanced”.

“Every day we are moving forward. Milestones are being achieved every day,” he said.

“We will break ground within days to mark the official start of work on the rail link.”

Adani’s announcement comes just days after a Roy Morgan survey of 1,547 people found 77 per cent of those who knew about the mine thought it should not go ahead.

Adani is still seeking a federal government concessional loan of around $900 million for the rail line from the Northern Australia Infrastructure Facility.

Adani says it is also looking overseas to secure finance by March 1.

The company needs to refinance $1.48 billion of borrowings on the Abbot Point port by November 2018. It is also looking to back a cumulative debt of $2.11 billion – more than the value of the port – by 2020.

Westpac has now joined another of the port’s original financiers, Deutsche Bank, in announcing a new climate policy that only allows it to invest in existing coal basins. Analysts say this could rule out any refinancing.

Adani still has to register an Indigenous land use agreement with the mine site’s traditional owners, while facing continuing legal challenges from within the group.

Adani has spent $3.5 billion in Australia so far, funded entirely through debt.

Mr Janakaraj said the pre-construction work was funded by about $400 million from Adani Enterprises in India.

The work includes “cultural heritage inspections and recordings” at the mine and rail sites.