Annette King says health workers are not taking annual leave.

More than 750 Taranaki hospital workers are owed over $14 million in time off, new figures reveal.

It means that 44 per cent of staff at the Taranaki Base Hospital - 755 workers - are owed more than four weeks of annual leave - the fourth highest figure among the country's district health boards.

The Labour Party said earlier this month that the 20 district health boards owed a collective $465 million in annual leave.

Annette King, the party's health spokesperson, warned that staff who did not take time off risked becoming stressed and tired "and that's a recipe for disaster".

But Taranaki's health bosses said they were aware of the situation.

George Thomas, manager of finance for the Taranaki District Health Board (TDHB), said it was aware of the numbers of staff with high balances of annual leave.

"Historical annual leave balances accrued by long-term employees tends to influence the more recent annual leave data," he said.

"Once an employee has achieved five years of service they are entitled to five weeks' annual leave."

Thomas said the TDHB worked with staff who have large annual leave balances and actively monitored and budgeted for outstanding time off.

"The majority of planned leave is managed within staff rosters," he said.

Thomas said relief/pool rosters were in place for junior doctors and nurses, while senior staff managed leave internally so essential services were never left un-staffed.

Labour health spokesperson Annette King said in a statement on November 8 that the amount of annual leave owed to staff could affect patient care.

"Our health professionals work incredibly hard, often forgoing overtime and meal breaks or working when they are sick to support their colleagues," she said.

"If frontline staff are not taking annual leave, which they are entitled to, then they will be stressed and tired and that's a recipe for disaster."

"Not only is patient care compromised, but lives could be put at risk."