The House-Senate energy tax conference is at a standstill because Sen. Russell B. Long (D-La.) refuses to settle the tax issues until a separate conference committee decided how large a price increase to allow on natural gas.

House conferees are grumbling that Long, leader of the Senate conferees, is holding President Carter's energy-saving taxes hostage until the other conference produces a natural gas bill he likes. Long is a strong supporter of lifting price controls from newly discovered natural gas - which Carter and the House oppose - and of greater production incentives - meaning tax cuts for producers - than Carter or the House want.

"If I was in his position, I guess I'd be doing the same thing," said Rep. Thomas L. Ashley (D-Ohio), who, as House Speaker Thomas P. (Tip) O'Neill's personal representative on the energy conferences, has been meeting privately each day with Long in an effort to get serious bargaining under way. But the House can play the same game, said Ashley: House members won't sign a conference report on gas until an acceptable tax package is produced, he declared.

The energy conference weas expected to be one of the toughest in memory, since the House had approved Carter's tax and natural gas price regulation proposals and the Senate rejected all of them. But the conferees appear determined to set a new record for inactivity. Yesterday, after eight days of meetings, the tax conferees had not settled one major difference and had made no serious public effort to do so.

Long said yesterday, he does feel the decisions on Carter's crude oil tax and other major tax issues should wait until the natural gas conferees have finished their work - but not because he wants to use it as a club to win natural gas deregulation.

The Senate appointed different members as conferees on the tax and non-tax parts of the energy package, but the same 25 House members are conferees on all parts of the package. Long said the House conferees working on natural gas and other non-tax provisions would want to take part in the tax decisions and that it was only fair to wait for them.

At the present pace, it appears unlikely that the non-tax conferees will reach the natural gas issue until next week.

Ashely said that unless the major issues separating House and Senate are resolved by the end of next week it will become increasingly difficult to take final action on the energy legislation this year. O'Neill has insisted previously that Congress would not quit for the year without passing the energy bill. But yesterday he said only that he was still "hopefully" of passage.

During more than a decade as chairman of the Senate Finance Committee, Long has acquired a reputation for getting his way in conference by sitting back and just waiting until the pressure of time makes House members come more than half way to meet him.

"I'm an optimist," Long said after yesterday's meeting. "I think there is a chance to pass a good bill in all respects." Asked what the conferees had accomplished to date, Long said they were talking, laying out their differences and gaining a "better understanding of what the parameters are."

Rep. Al Ullman (D-Ore)., chairman of the House Ways and Means Committee, said, "Even though it may look as if we are not making progress, I think we are and will have an effective bill."

The House leadership has to make a deal with Long that is acceptable not only to Carter, but to young liberals who think even Carter's original bill gave away too much to the oil and gas industry. They may now be asked to approve a much higher price for natural gas than they want in order to pry loose from Long the Carter crude oil tax, which thay also oppose as a regressive sales tax on the poor.

Conferee Toby Moffett (D-Conn.) speaks for nearly 70 young House members who have theatened to vote against the final version of the bill if it would deregulate new natural gas and give the oil industry a slice of the revenue from the crude oil tax.

The Senate voted to create an energy trust fund which would be a vehicle for giving production incentives to the oil industry. When Assistant Treasury Secretary Laurence Woodworth told the tax conferees yesterday that the administration does "not oppose the trust fund as such" though it is opposed to a plowback to the industry to explore for more oil. Moffett accused the administration of "undercutting" the position of the House as it tries to save the President's energy bill.

Moffett said Energy Secretary James R. Schlesinger had assured a group of pro-consumer congressmen and lobbyists on Monday that the administration is opposed to creating an energy trust fund. That Long said, simply showed Carter had appointed "such capable people they are all able to have an idea of their own."