Volunteers who raised up to €4,500 to travel with a leading Irish charity to the cholera hit island of Haiti are to be asked to raise an additional €1,500 if they still wish to participate in the postponed trip. The Haven charity – which was forced to cancel its plans to bring 600 volunteers on two 'Build it' week excursions to the country due to the outbreak of the disease – is to hold a series of meetings for volunteers later this week in Dublin, Cork and Galway where it will outline the situation.

It now hopes to reschedule the original trips for May of next year, but says it is fully aware that this might not suit some of those who previously raised the requisite funds with the intention of participating in the intensive construction initiative this year.

Participants were required to raise €4,500 if they were "new" volunteers, with previous or repeat volunteers asked to raise €4,000. This money covers the cost of flights, food and other expenses, with the remainder used to buy the necessary building materials for the initiative.

A spokeswoman for Haven confirmed it had begun contacting the volunteers last week to inform them of the revised plan. She said it had taken the "difficult decision" to ask volunteers to raise the additional €1,500 and was "absolutely aware" of how tough this might be for some of those involved.

While the charity had cancellation insurance, this policy did not cover a decision to postpone the trip, which it had taken to ensure the health and safety of the volunteers.

As a result, it was not entitled to receive a refund of the flight monies from the insurance company, and could not afford to pay for these itself.

"This is the last thing we wanted to do... we have managed to have a certain amount of the money refunded but not the full amount," she said. "The extra €1,500 is to pay your way. But we absolutely understand if people cannot raise this extra money."

Cholera, which spreads through contaminated water and food, has now claimed 724 lives in Haiti, which was already reeling from the effect of January's earthquake that left more than 250,000 people dead.

"When you are signing up for a trip like this, you really do fundraise for the charity. And the 'Build It' week is the penultimate part of it," the Haven spokeswoman said.

"Unfortunately, you can't guarantee anything in Haiti. The decision to cancel was one of the hardest decisions Haven has had to take."