HARRISBURG — Tom Wolf may not hold an elected office yet, but as Democratic gubernatorial nominee, he is pressing Republican Gov. Tom Corbett and legislators in both parties to approve a tax on natural gas extraction that would generate hundreds of millions of dollars.

Wolf’s campaign said Tuesday that he was sending letters to Corbett and members of the state House and Senate, urging them to “put politics aside” and pass a 5 percent severance tax.

“Pennsylvania should not be the only major gas-producing state without a severance tax,” the York businessman said in his letter to lawmakers.

Corbett’s campaign and his Republican allies in the Legislature said it is premature to consider raising taxes, particularly such a massive increase.

Wolf is “no different than your stereotypical Democrat. His first response is higher taxes,” said Steve Miskin, a spokesman for the House Republican leaders. “It’s not leadership to jump right in and advocate a tax” increase.

The governor told leaders of the GOP majorities in both chambers Monday that he opposes raising taxes and would prefer to reduce spending and tap existing sources of money to offset a potential $1 billion-plus shortfall.

“He’s very concerned that a tax increase could hurt the industry and cost jobs,” said Mike Barley, the governor’s campaign manager. Legislators in both parties and both chambers have expressed support for the idea of a severance tax to ensure that the state shares the industry’s wealth and to bolster revenue for schools and environmental protection.

A 5 percent tax would generate an estimated $700 million in the first year, according to Senate Democrats.