DOVER — Another proposal by Democrats to increase the state’s gasoline tax appears to have stalled before even reaching bill form.

Several Democratic legislators revealed in February they wanted to temporarily raise the tax by 10 cents per gallon. But the idea has thus far not been introduced as legislation. And it seems unlikely that it will now, one sponsor said Tuesday.

Rep. Michael Mulrooney, D-Wilmington Manor, said he does not think the proposal has enough support to pass and so will probably not become a formal bill.

Tax-hike supporters still are attempting to gain votes, but many lawmakers are adamantly opposed to an increase. Even if every Democrat voted for the measure, it would also require Republican backing.

Gov. Jack Markell, a Democrat, proposed a 10-cent-a-gallon tax increase in 2014, but the idea went nowhere. Democratic lawmakers tried to drum up support for a smaller tax hike last year, but to no avail.

This year’s effort seems likely to end the same way.

Another controversial proposal could still move forward.

Rep. Mulrooney said he still intends to have House Bill 283, which would give unions more control over the terms of state projects, heard on the floor. It also would require 30 percent of workers on state-funded construction reside in the representative district where the project is and 5 percent of laborers be military veterans.

Hundreds of workers and business owners turned up at the committee hearing last month to oppose the bill which has received strong support from Democratic lawmakers and unions.

The legislation was released from committee but has not made it to the floor, as supporters attempt to address objections raised by opponents.