The minister, Fadillah Yusof, called for proper documentation to back the proposal, saying that approval could not be granted based only on a letter.

Fadillah said that it was not standard practice for the federal government to approve a multi-billion ringgit project “without a single piece of documentation”.

The application should also be free of political rhetoric, he said. “For example, terms like ‘anasir-anasir jahat’ (destructive elements) are not helpful and not typically found in an application letter for major infrastructure,” Fadillah said in a statement today quoted by Malay Mail Online.

He pointed out that even planning permission applications to the Penang local councils required supporting documentation and that approvals in principle were not granted based on only a letter.

Penang chief minister Lim Guan Eng had written a letter addressed to the prime minister, Najib Razak, on May 26.

Fadillah said Lim should have submitted the application to the ministry and not directly to the prime minister.

He said his ministry would make a fair evaluation of the proposal for a third bridge and asked the state government “to share with us all the relevant documentation, so that we are able to make an informed decision in the best interest of the rakyat”.

“One major document would be the almost-completed RM305 million feasibility and detailed design studies commissioned and paid for by the Penang government for the undersea tunnel project and associated linked roads,” he added.

The state government had commissioned the feasibility study for its proposed cross-Channel tunnel to the mainland.

Federal approval was needed to build a third bridge, but the state could proceed on its own for the tunnel, which it proposes to pay for by awarding land reclamation rights.

Fadillah noted that the state government had previously said the feasibility study would not go to waste if a bridge was built instead of the tunnel as either project would be on the same alignment.

“If that is the case, submitting these documents to us would assist us in our decision-making,” Fadillah said.

“The Works Ministry looks forward to working together with the Penang state government to ascertain the feasibility and timing of the proposed third link to the mainland, in a professional manner,” the statement said.

The proposed RM6.3 billion tunnel was announced by the state government in 2012 as part of the RM28 billion Penang master transport plan, which has created controversy over plans for massive reclamation off the south coast in order to pay for the costs.

Construction was to have started this year for completion in 2025.