Leaked pamphlets, to feature in an upcoming campaign against same-sex marriage, suggest children of gay and lesbian parents are more prone to "abuse and neglect" and more likely to be unemployed, abuse drugs and suffer depression.

The pamphlets, which have been authorised by a former parliamentary secretary to John Howard, indicate the potential lines of attack for the "no" campaign at a national plebiscite on same-sex marriage.

Labor and marriage equality campaigners have argued against a plebiscite, saying it will unleash divisive attacks on the gay and lesbian community. Prime Minister Malcolm Turnbull has said he has faith Australians will participate in a plebiscite in a civil and sensible manner.

The government is finalising the mechanism for the plebiscite to be held after the next election.