(Updated at 2:15 p.m. with Case’s response)

The national Democratic Party is issuing a rare reprimand of one of its Senate candidates, speaking out against a poll released by former congressman Ed Case in the Hawaii Senate primary.

The Case poll, conducted by the Merriman River Group, showed him leading Rep. Mazie Hirono in a primary for the seat of retiring Sen. Daniel Akaka (D) by 16 points.

But the more objectionable part of the poll, according to the Democratic Senatorial Campaign Committee, is that it showed Case leading former Republican governor Linda Lingle by 10 points, but Hirono trailing Lingle by five — a gap of 15 points between the two Democrats in a general election matchup.

DSCC executive director Guy Cecil accused Case of not “being honest” with the poll. “It exaggerates support for him and for Lingle,” Cecil said. “It also contradicts polling we have done in this race that shows Hirono leading Lingle by 19 points.”

In a statement sent to The Fix, Case stood by the poll and said Democrats should be wary of who their nominee is.

“One message of this poll is that national Dems should care very much about who is their nominee and should not take Hawaii for granted in the general,” Case said.

Merriman River Group executive director Matthew E. Fitch told The Fix that the poll is one of three the firm has conducted in the race, and that the results echo the other two polls. He also noted that the group has lots of experience polling in the state and was very close to predicting the result of a 2010 special congressional election in which Case was a candidate.

“It’s the nature of primary and defining likely voters,” Fitch said. “Our poll is pretty exact as far as finding actual voters.”

The DSCC’s poll, conducted by the Mellman Group earlier this year, showed Hirono leading Lingle 54 percent to 35 percent. The DSCC wouldn’t say whether it polled Case as well.

And a Ward Research poll conducted in May for the Hono­lulu Star-Advertiser showed Hirono leading Lingle by 22 points and Case leading her by 18.

The DSCC hasn’t taken sides in the primary, but it’s rare for a national party committee to speak out publicly against one of its candidates in a primary. At the same time, this isn’t the first time that Case has irritated the party establishment.

In 2006, Case made plenty of enemies, including Sen. Daniel Inouye (D-Hawaii), when he decided to challenge Akaka in a primary. Inouye said Case had lied to him by saying he wouldn’t pursue the race. Akaka won the primary 55 percent to 45 percent.

Then, in 2010, Case muddied the waters in a free-for-all special election for one of the state’s two House seats, splitting the Democratic vote with Colleen Hanabusa and allowing Republican Charles Djou to win the seat with less than 40 percent of the vote. Later, in a head-to-head matchup in November, Hanabusa beat Djou

Lingle is not officialy a candidate but is weighing the race. She is seen as one of only one or two Republicans — including Djou — who could potentially make the race competitive. But winning in strongly Democratic Hawaii with President Obama on the ballot will be a tough slog for the GOP.

Democrats have already begun tying Lingle to former Alaska governor Sarah Palin, whom Lingle introduced at the 2008 Republican National Convention.

Hanabusa hasn’t ruled out running, but Emily’s List, which supports Democratic pro-abortion rights female candidates for office, has already endorsed Hirono.