668.6  Enforcement of contribution.
  1.  If the percentages of fault of each of the parties to a claim for contribution have been established previously by the court as provided in section 668.3, a party paying more than the party’s percentage share of damages may recover judgment for contribution upon motion to the court or in a separate action.
  2.  If the percentages of fault of each of the parties to a claim for contribution have not been established by the court, contribution may be enforced in a separate action, whether or not a judgment has been rendered against either the person seeking contribution or the person from whom contribution is sought.
  3.  If a judgment has been rendered, an action for contribution must be commenced within one year after the judgment becomes final. If a judgment has not been rendered, a claim for contribution is enforceable only upon satisfaction of one of the following sets of conditions:
  a.  The person bringing the action for contribution must have discharged the liability of the person from whom contribution is sought by payment made within the period of the statute of limitations applicable to the claimant’s right of action and must have commenced the action for contribution within one year after the date of that payment.
  b.  The person seeking contribution must have agreed while the action of the claimant was pending to discharge the liability of the person from whom contribution is sought and within one year after the date of the agreement must have discharged that liability and commenced the action for contribution.
84 Acts, ch 1293, §6