Auckland Regional Council chairman Mike Lee has hit back in the debate over Auckland's transport options by promising to send the Transport Minister a "courier van load" of documents proving the case for rail electrification and building a tunnel under the central business district.

The minister, Steven Joyce, said in the Weekend Herald that more work was needed to set out the business case and land use planning effects of certain public transport projects.

The Auckland Regional Transport Committee wants public transport, particularly rail electrification, an airport rail link and a central-city rail tunnel to Britomart, to be given equal spending priority with roads.

That may put it at odds with Government plans to prioritise a $2.3 billion motorway extension north from Puhoi to Wellsford.

Mr Lee said he believed Mr Joyce was engaged in delaying tactics to put off buying electric trains for Auckland.

"He is starting to run with the idea that there is no planning or very little planning to justify spending on public transport upgrades on the Auckland isthmus ... and there has been a veritable truckload of the stuff," he said.

"We are starting to see it as, 'Here we go again, another excuse why he has delayed the purchase of electric rolling stock for Auckland'."

But Mr Joyce said there were no plans to delay spending on electrification.

His comments to the Weekend Herald had referred to two longer-term projects - the rail tunnel and a rail link to the airport - not electrification, he said.

Mr Lee last night sent the minister a bundle of documents by courier which he said would answer Mr Joyce's concerns.

Mr Joyce said he had seen summaries of some of the existing reports but, if the projects were to get Government funding, all relevant parties, including the Super City council, would need to agree on the assessments of costs and effects.

"There are a number of things we would need to do besides just saying 'I want a CBD rail tunnel'," added Mr Joyce.