MINNEAPOLIS — Around 4,800 nurses are preparing to launch a one-week strike today at five hospitals in the Minneapolis-St. Paul area in a dispute over health insurance.

Minnesota Nurses Association members planned to walk out at 7 a.m. today at hospitals operated by Allina Health — Abbott Northwestern in Minneapolis, Mercy in Coon Rapids, United in St. Paul, Unity in Fridley, and the Phillips Eye Institute in Minneapolis.

Allina said it plans to keep the facilities operating close to normally with a smaller staff of replacement nurses.

Officials on both sides said Friday that there was no chance of averting the strike.

The main dispute is over Allina’s effort to switch union nurses to the same health insurance plans as other Allina employees, which carry lower monthly premiums but higher out-of-pocket costs.