Both sides in the race for governor described a kind of campaign finance arms race, especially in the area of independent expenditures, which faced few restrictions in New Jersey even before the Citizens United decision by the Supreme Court forced many states to rewrite their election laws.

Four years ago, Mr. Christie relied heavily on advertising help from the R.G.A. in his underdog victory against former Gov. Jon Corzine, a Democrat and wealthy former Goldman Sachs executive who spent $25 million of his own money running for re-election in 2009. Mr. Christie, like other governors, has been a frequent headliner at the association’s fund-raisers.

After Mr. Christie took office, friends and advisers, anticipating an onslaught of spending from labor unions, began raising donations outside the state’s traditional campaign finance channels to pay for advertising in support of Mr. Christie’s legislative agenda.

About $624,000 went to Reform Jersey Now, a nonprofit group that advertised Mr. Christie’s attendance at one fund-raiser by advising donors that “contributions are not affected by the pay-to-play statutes.” Reform Jersey Now shut down after six months and voluntarily disclosed its donors, many of them state contractors.

Ms. Buono was among those who criticized Reform Jersey Now, saying they “render our campaign finance and pay-to-play laws useless” and introducing legislation that would have required the group to disclose its donors. But after the group shut down, three Democratic consulting firms, including two that worked for Ms. Buono, started up One New Jersey to battle the governor. In May, allies of Ms. Buono in the State Assembly quashed a disclosure bill identical to the legislation she herself had sponsored.

Joshua Henne, a spokesman for One New Jersey, declined to comment on the group’s donors, or to say whether any of them had contracts with state agencies or authorities covered by the pay-to-play rules.

All told, at least 15 New Jersey donations to the governors association this year have come from people or companies covered by the state’s pay-to-play rules, including several who also backed Reform Jersey Now. Some had never given to the R.G.A. before.