Attorney General George Jepsen and Consumer Counsel Elin Swanson Katz want regulators to find out why Northeast Utilities, the parent company of Connecticut Light & Power and Yankee Gas, failed to inform the state of layoffs.

Notifying the state of any layoffs was a requirement of Northeast Utilities’ merger with NSTAR last March, Jepsen and Katz say in this letter to regulators.

In a filing with the Public Utility Regulatory Authority, Northeast Utilities says 319 employees have left the utility since the merger. NU says that the layoffs were “explicitly contemplated during the merger proceedings” and don’t trigger the reporting requirements in the March settlement agreement. NU says the 319 employees cited by the two doesn’t account for the 155 employees the utility has hired since the merger.

“Every termination related to the merger is a layoff” and should be reported to the Attorney General’s office, as well as the Office of Consumer Council, Jepsen and Katz argue in the letter.

They add that a “full detailed demonstration of proportionality” also is required to make sure that Massachusetts-based NSTAR and Connecticut-based Northeast Utilities are being treated proportionally.

But Northeast Utilities disagrees. But because the matter is pending with state regulators, there’s not much the utility can say.

“As we have said before, our merger does not include plans for broad layoffs,” Al Lara, NU spokesman, said in a statement. “The elimination of redundant positions existing in both companies in our corporate functions was expected and is required to achieve efficiencies and savings for our customers as a result of our merger.”

But Jepsen and Katz are afraid the utility is hiding behind the merger, which is why they’re asking regulators to dig deeper into the issue.

Jepsen and Katz asked regulators to force the utility to provide information about the company’s layoffs within 10 days.