PORTLAND — The former Roman Catholic bishop of Maine is urging the state’s Catholics to vote against efforts to legalize gay marriage in the state.

In a statement Thursday, Bishop Richard Malone said Catholics who support same-sex marriage are “unfaithful to Catholic doctrine.”

A gay marriage referendum is on the ballot Nov. 6.

Malone, now administrator of the Maine diocese after being appointed bishop of the Buffalo, N.Y., Diocese, says a “Catholic whose conscience has been properly formed by scripture and church teaching cannot justify a vote for a candidate or referendum question” that opposes church teachings.

A group called Catholics for Marriage Equality says it’s placing ads in three Maine newspapers urging residents to support gay marriage.

Malone calls the organization, as well as a group that supports abortion rights, “dissident” groups.