Parkdean Holidays yesterday reported a £4m rise in losses as its increased portfolio ran up bigger off-season bills.

The Newcastle plc revealed pre-tax losses for the six months to April 30 of £9.6m, compared to £5.6m for the same period last year.

Turnover for the period increased by more than £6m to £19.44m.

The figures include the winter season, and the company said it remained on track to improve on last year's £9m profit.

Chairman Graham Wilson said: "It is turning out to be a challenging year, but it is by no means a disaster."

He attributed the rise in losses to the growth of the estate, which has acquired six holiday parks in the past year, taking its portfolio to 20.

The group, which has parks in Scotland, South Wales and Cornwall, is planning to acquire more sites across the UK, including in Yorkshire.

"We are always looking for new sites across the country," he said.

"We are not well represented in Devon or Dorset and would also like something in Yorkshire and the Lakes."

Mr Wilson blamed part of the decline on the growing pressure on parents not to take children out of school for term-time holidays.

However, he predicted the summer would more than compensate.

"We still have some capacity to sell for our peak times in July and August, but we are confident that they will sell out - there is no reason to suggest that won't be the case."

The company revealed that holiday sales had been "erratic", with a lull in bookings around the time of the General Election and then again early this month.

Sales since April are down 4.1 per cent on last year, with parks in Cornwall seeing the slowest start to the season.

There has also been an increasing shift towards people booking shorter holidays.

However, overall sales are up 27.1 per cent on last year and end-of-year results are expected to at least match last year's.

"In March, we had the group's 20 properties valued at £182m - about £30m more than they are on the books for, so that is a positive," said Mr Wilson.

Investors will receive an interim dividend of 2.8p a share - up more than a quarter on last year.

Mr Wilson said: "The board have in place strategies that will enable Parkdean to resume its normal growth pattern in 2006 and our confidence in our business model is reflected by the increase in the declared interim dividend."