Under Pharmac rules, the Mirena is funded only for women with heavy menstrual bleeding.
The funding will pay for the $3 Pharmac prescription charge, doctor and nurse fees - which range from zero for young women at some clinics to $200 - and the materials charge of about $20 for Jadelle implantation.
A women's health group and Family Planning have welcomed the increased access to contraceptives, but say it should be for more women than just those supported by welfare.
Mangere Budgeting and Family Support Services chief executive Darryl Evans said some of the beneficiaries he had spoken to about the new policy yesterday believed the Government would pressure people into contraception against their will.
"I'm a believer in freedom of choice. People should decide for themselves whether they go on contraception ... This is not communist China."
But Julie Whitehead, of the Auckland Single Parents Trust, welcomed the policy, saying: "A lot of these girls don't know there's more to life than having babies."
Putiputi Wikohika, one of several women interviewed outside an Auckland Work and Income office, said Winz staff would pressure women into using contraceptives.
Ms Wikohika, who has been a beneficiary on and off for 20 years and who has had five children, claimed she had already been told by a case officer to "shut your legs".
Sandra Waru, who has been on a benefit for much of her life, said of Winz staff: "I think they'll do whatever the Government tells them to do. I think they'll push [contraception on women]."
But Naomi Grey, 23, disagreed. "... it might be somewhat of a good idea to encourage people on the benefit not to have children because they can't really afford to pay for themselves at the moment, so they shouldn't really be having children."
Mother-of-three Rudinia Smith, 22, who is on a broadcasting course, said she didn't try to have children in order to receive the benefit, but was "less careful" as she knew she would be helped financially.
The policy was a good idea, she said, as long as women weren't pressured to take contraception as soon as they had a baby.