State utility regulators on Wednesday ruled they have the regulatory jurisdiction to review the proposed $4.7 billion merger of Northeast Utilities and NSTAR.

The Connecticut Public Utilities Regulatory Authority, or PURA, issued a final decision stating it will review the mega-merger of the utilities, affirming a draft decision earlier this month that it would look into the deal that would combine the Hartford-based Northeast Utilities with the Boston-based NSTAR.

The proposed merger, if approved by regulators and shareholders, would create one of this nation's largest utilities, serving more than 3 million utility customers across several New England states.

The regulatory agency said in its final decision Wednesday that it is legally obliged to review the proposed merger to ensure that after any such deal, Connecticut Light & Power and Yankee Gas Services would still be able to provide "safe, adequate, reliable and reasonably-priced services" for its customers across the state.

CL&P and Yankee Gas are among the largest subsidiaries of Northeast Utilities, and both provide services in southeastern Connecticut. Northeast Utilities other holdings include Western Massachusetts Electric Co., Public Service of New Hampshire and NU Transmission.

Wednesday's decision also contains an order that Northeast Utilities cannot complete the merger until state utility regulators have issued a final decision giving a green light to the nearly $5 billion utility deal. The decision does note an analysis presented by Attorney General George Jepsen regarding the significance of any possible management changes that would occur under a merger of Northeast Utilities and NSTAR.

Jepsen has said that Connecticut consumers deserve a meaningful and thorough review process of the proposed merger. The attorney general also has said that Northeast Utilities' much-criticized response to Tropical Storm Irene and the October snowstorm raised a "significant issue about the utility's management and its executive leadership" that needs to be addressed by state utility regulators.

NSTAR, which is Massachusetts' largest investor-owned electric and gas utility, has revenues of about $3 billion with assets totaling about $8 billion. The company transmits and delivers electricity and gas to about 1.1 million electric customers across 81 cities and towns. In addition, it provides natural gas services to about 300,000 gas customers in 51 municipalities. NSTAR employs more than 3,000 in its regulated businesses.

Northeast Utilities operates New England's largest utility system, with more than 2 million electric and gas customers in Connecticut, western Massachusetts and New Hampshire.