The clamp forced on elective surgery by the resident doctors' strike is fuelling fears hospitals will be financially penalised for their delays.
The Health Ministry can withhold some funding to sting district health boards which don't comply with elective surgery targets.
Thousands of patients have had elective procedures or outpatient appointments delayed so hospitals can focus on providing safe emergency and acute care during the strike.
It's almost inevitable we will be non-compliant with the elective surgery target
The 73-hour strike by members of the Resident Doctors' Association enters day two tomorrow and will end on Friday at 8am.
Northland DHB chief medical officer Dr Mike Roberts said things were "going okay" at Whangarei Hospital but the management was concerned by the ongoing effects the strike could have on elective surgery.
"It's almost inevitable we will be non-compliant with the elective surgery target."
He was referring to the Government's requirement that patients receive promised surgery within four months.
Meeting the target was difficult in normal times, he said. The surgery postponements from the strike made this worse.
When asked if other DHBs might be at risk of being similarly penalised, Roberts highlighted the level of non-compliance.
Northland had not met the target for 1 per cent of patients in November. The performance of nine other DHBs was worse and Roberts said December and January were typically difficult times to meet the target.
He said four months' non-compliance put a DHB at risk of a financial penalty. For Northland it could mean losing $1.5 million - one month's payment of an annual $18 million in "discretionary" funding for its elective services. The loss - 2 per cent of total electives funding - would have to be spread across all the DHB's services.
For each subsequent month of non-compliance, the same amount could be withheld by the ministry.
"They initially said there was not going to be any leniency [relating to the impact of the strike]. They have now said that they are waiting to have a conversation with chief executives ... this week and may change their stance."
Roberts was also concerned that DHBs would not receive any extra state funding to cover the likely increased costs from agreeing to the association's demands, and that the level of care for patients would be eroded.
The ministry said it couldn't comment on Roberts' statements tonight, but would do so tomorrow.
A spokeswoman for the 18 district health boards affected by the strike (the West Coast and Taranaki DHBs are not affected) said they coped well during day one.
"Things seem to be going reasonably well at this point," said the national co-ordinator of contingency planning, Anne Aitcheson.
"All hospitals reported having capacity to take additional patients and were expecting more discharges once the SMOs [senior medical officers] had done their rounds.
"Tomorrow it will be much more around how many acute admissions have we had, and getting surgery completed and they could fill up again. That's why we defer some elective work so we can accommodate and manage those patients."
At least 3025 association members are eligible to strike, but there were reports of members working at some hospitals today, including 14 at Northland DHB, where a further 15 - of 104 resident doctors in total - are non-members and working.
In talks with the union, the DHBs have agreed to reduce rosters of 12 days in a row, which were considered a risk to patients and the doctors who worked them, to 10 days.
The Herald understands this typically results in around 15 more days off a year. The union proposed that members would not be paid for about one-third of the extra days.
However, the union also wants members to be able to take the days off around weekends and the DHBs have not agreed to this, arguing it would leave them with too few resident doctors at key times, especially on Mondays and Fridays, and too many on Wednesdays.