The charges carry a maximum penalty of $250,000.
Willis St Parking's lawyer, Noel Sainsbury, yesterday argued in Wellington District Court that the potential harms posed by the asbestos and the live electricity were two separate matters of different seriousness, and should be dealt with in different charges.
The department's lawyer, Greg La Hood, argued for the charges to remain as they were.
Judge Chris Tuohy today ruled two distinct harms were alleged in the charges and it could be duplicitous to cover both in a single charge.
He ordered the Department of Labour to set out the particulars of each harm in its charges.
The case returns to the court on December 20, when the department is expected to present its amended charges.