In a letter to Gov. Linda Lingle, Mayor Mufi Hannemann asks for written justification of why the state won't begin to collect the transit tax surcharge in January as required by state law and holds out the possibility of legal action to force compliance.

Lingle said this week that the state Department of Taxation can't hire a private company to begin collecting the additional tax because the state Legislature didn't set aside any money for that cost. The city is counting on the increase in the general excise tax on O'ahu — from 4 percent to 4.5 percent — to provide about $150 million a year for a mass-transit system in Honolulu.

Hannemann's letter requested a response by next Friday as to why the transit surcharge cannot be collected by the state.

"Should the state Department of Taxation decide or indicate its intention not to collect the county surcharge on state tax in accordance with Act 247, the city will be left with no choice but to seek a court order to enforce the terms of the act and require the state Department of Taxation to collect the county surcharge on state tax," Hannemann wrote.

In a news conference, Hannemann said he would prefer to settle the matter out of court and would like to work with the state on finding a way to collect the tax that works well for all parties.

Hannemann and Lingle traded spicy rhetoric this week over the politically sensitive tax to pay for transit.

Hannemann has said it is not a personal battle. He signed yesterday's letter "with warm regards and aloha."

Any roadblock to the longdebated transit project worries supporters, who have come close to approval of mass transit in the past only to see plans fall apart.

Such a project is expected to be the largest public works project in the state's history.

Lingle spokesman Russell Pang said the governor was on Maui yesterday but that her office had received the letter.

"We will review the letter and respond to the mayor accordingly in a timely manner," Pang said.

Reach Robbie Dingeman at rdingeman@honoluluadvertiser.com.