Two women have been arrested after allegedly importing methamphetamine into Dunedin and Nelson, which had a value of nearly $1 million.

A police operation targeted an organised crime group smuggling the drug, which lead to the arrests of the women, aged 40 and 28.

The pair are facing multiple charges of importation of a class A drug and conspiracy to deal and supply meth.

This level of importation is a major concern as the use of methamphetamine has no positive outcomes, says Detective Senior Sergeant John Fergusson.

"This is a particularly nasty drug that not only adversely affects the users, but also causes significant harm to the family and friends of those using the drug."

Both women have been remanded in custody and will appear in Dunedin District Court on December 15.

Police say additional people could be charged.