He said it is the seventh busiest airport in the country with 70 plane movements per day.
"It is essential for the safety of passengers and for the continuing success of our region that this issue is addressed as soon as possible."
Yule said he is asking the Minister in charge to address this issue promptly and is seeking reassurances from the CAA.
The New Zealand Air Line Pilots' Association (NZALPA) president Tim Robinson shared similar sentiments, noting they continue to have concerns due to the increased numbers of New Zealand airspace closures, particularly in Napier.
"Our pilots rely on Air Traffic Control for safe and efficient conduct of flights, and we feel this is being compromised by the increasing frequency of contingency procedures and reduced capacity notices across the Airspace system of New Zealand."
Airways NZ general manager Air Traffic Services, Tim Boyle, said they expect normal operations to resume this month.
He admitted the situation is "highly unusual", with three of the five staff unavailable for work.
"The majority of flights have been able to operate normally into and out of Hawke's Bay Airport while contingency procedures have been in place. However, we are aware that there have been delays to some flights," Boyle said.
"We are disappointed that we have not been able to provide our usual high level of service from Napier Tower and apologise to any travellers who have been affected."
Contingency airspace procedures have been put in place to allow flights to continue to operate safely when the tower has been unstaffed.
When contingency procedures are in place, the number of aircraft able to fly in the airspace surrounding the airport is restricted and pilots use standard visual separation rules to stay safely separated.
Air traffic controllers based in Airways NZ radar centre in Christchurch continue to monitor the aircraft once it reaches airspace covered by radar, Boyle said.
It is the same process pilots follow on a daily basis at airports without air traffic control towers, like Taupo, Whangarei and Kerikeri.
Boyle said they have brought in four controllers, who are now trained and certified to work in the Napier tower, from other units around the country to boost staff numbers.
In the long term, they plan to have permanent staff back on the roster.
Hawke's Bay Airport operations manager Gareth Mentzer said they are working with Airways NZ. While they have seen some minor improvements recently, Mentzer said they still wanted to see significant focus from Airways to improve the staffing levels.
"Any potential impact on passenger numbers is difficult to quantify, however, there has been disruptions to services which have inconvenienced customers, which is clearly of concern."
