In one of the first polls in the hotly-contested and high-priced US Senate race in New Mexico, Public Policy Polling (PPP) says Democrat Martin Heinrich has a 5-point lead on Republican Heather Wilson but some GOP loyalists say the poll is skewed to favor Democrats.

PPP, based in North Carolina and associated with the Democratic Party, released its poll on Tuesday (July 17) showing that Heinrich is at 48 percent, Wilson is at 43 percent with 9 percent undecided.

In the poll of 724 New Mexico voters conducted between July 13-16, 52 percent of the respondents in the phone survey identified themselves as Democrats, 33 percent as Republicans and 16 as Independent/Other.

“Is anyone not surprised to learn the latest #NMSen survey by @ppppolls oversamples Dem voters by 5 pts? Always check the fine print w them,” tweeted Brian Walsh, the communications director of the National Republican Senatorial Committee (NRSC).

Registration in New Mexico is 48 percent Democrat and 32 percent Republican. The PPP poll had a 50-50 split between white and non-white voters and had a margin of error of plus or minus 3.6 percent.

While some Republicans might complain about the Heinrich-Wilson numbers, PPP shows that GOP Gov. Susana Martinez is still posting impressive polling stats.

Some 56 percent of those surveyed approved of the job she’s doing and 34 percent disapprove.

“What’s most striking in her numbers is that Democrats nearly break even on her with 44 percent approving and 45 percent disapproving,” Tom Jensen of PPP wrote in a news release. “That crossover support has her ranked as one of the top ten most popular Governors in the country in our polling.”

Last week, New Mexico Attorney General Gary King announced he’ll challenge Martinez in the 2014 gubernatorial race. The PPP survey shows Martinez beating King 51-39.

State auditor Hector Balderas is being mentioned as a possible gubernatorial candidate and the PPP survey has Martinez beating him 50-37, although PPP reports that his favorability has gained 9 points since last year.

Balderas “may not have won the primary [against Heinrich back in June] but he emerged from it more popular and with better name recognition, which could position him to do something good further down the line,” Jensen wrote.

There’s also been talk that Balderas might run for the attorney general’s spot in 2014.

To see the PPP numbers, click here.