Workers in New Zealand are now allowed to use text messages from the Ministry of Health as proof of COVID-19 infection or household contact, but some businesses are worried that it might lead to abuse.

The Ministry of Health said employees can use text messages from the ministry as evidence of needing time off work. However, there are concerns that employees could exploit it.

The service comes at a point when general practices are dealing with a rising number of COVID-19 cases, the overflowing of hospitals, and the return of the flu in the country.

The ministry said text messages are "reliable evidence" that employees can use as evidence rather than seeking a medical certificate from a traditional GP, which creates additional work for them at a hectic time of the year.

According to the ministry, the ministry will send texts from 2328 or 2648 to a COVID-19 positive individual and any household contacts identified. 

The first text confirms their positive status and the need to isolate, while the second text message confirms that they can leave isolation and return to work if they are feeling well.

Meanwhile, household contacts will receive a text that says they are free to come out of isolation if their 7-day RAT result is negative.

However, the problem with text messages is that employees can message the ministry that they have COVID-19, regardless of the truth, and they will send the text.

In an interview with AM host Ryan Bridge, employment lawyer Jennifer Mills said that generally, an employee must provide a medical certificate if an employer requests it. However, the Holidays Act, which is about sick leave, does not require a medical certificate as evidence of sickness.

"Provided an employee can easily provide proof, then that ought to be accepted," she said.

Although employers can accept the text message and consider it sufficient, they can still question it, Mills said.

She said that if employers are concerned about the text's genuineness, they can then request a medical certificate from their employee from their GP.

Dr Bryan Betty, medical director of the Royal New Zealand College of Practitioners, told AM that the situation in the New Zealand health sector was "very serious."

He said the system has minimal spare capacity because of the flu, the significant number of COVID-19 cases, and the other winter viruses floating around. He said doctors and nurses are often sick, which slows the workforce.

Betty added that what is critically important now is that the capacity is open for those who need to be seen immediately and need the appointment. He said that it's a very challenging situation at the moment.