With the 2015 General Election coinciding with the Hungry Ghost Festival and continuing islandwide SG50 celebrations, as well as arrangements for the Formula One Singapore Grand Prix from Sept 18 to 20, business has been brisk for tentage rental firms.

In fact, the demand is greater than what the companies can handle, with several companies having to turn customers away.

But it has also driven up costs of staging rallies for political parties.

"The demand this time of the year compared with previous years is very different," said Ms Katherine Lee, director of Singapore Tentage.

"A lot of companies are organising events around SG50. A lot of our partners in the industry have run out of tentage materials and we've had to turn away a lot of jobs."

Her company has turned down about eight jobs to set up rally sites, taking on only about two such jobs.

Ms Lee said that business has improved by about 50 per cent and a shortage of manpower means workers having to work longer hours.

She added: "Many of our workers have had to work until late into the night to set up tentage, with just a few hours of rest before getting back to work."

She said that this has led to costs going up by 20 to 30 per cent and estimated that setting up a rally site costs $2,000.

Mr Ivan Ho, operations manager of Lian Hup Seng Construction, said: "We are fully booked.

"We had a lot of requests to set up rally sites but could not take up even one such job."

Most tentage companies, he added, rely on the revenue from the Hungry Ghost Festival to tide over the lull in business from November to March.

A Seng Heng Tentage Rental employee, who declined to be named, said workers have to be compensated for working longer hours.

"Trust is very important in our industry. If we take on a job, we have to be sure we set everything up before the event starts," she said.

Mrs Lina Chiam, chairman of the Singapore People's Party, had said that the timing of the elections has made it "rather challenging for the opposition".

The Potong Pasir SMC hopeful said that costs of holding a rally have doubled.

While it cost her party about $3,000 to hold a rally during the 2011 General Election, she has been quoted at least $4,500 for a rally site during this general election - excluding the cost of barricades, which she estimated would bring the final cost to $6,000.

Singapore Democratic Alliance chief Desmond Lim has also had to fork out more to hold a rally, paying about $11,000 for a night for the stage, sound system, barricades and generator, compared with $9,000 a night at the last elections in 2011.

"But we don't have a choice. Either we cut down on the number of rallies, or we cut down on other expenses, such as the printing of fliers," he said.

SingFirst campaign manager Patrick Loke said that there have been hiccups.

"They may not be able to supply all that we requested," he said, noting that the party had to work within a smaller space because of a lack of barricades.

"This is a busy period for the tentage rental companies, but prices are generally competitive."

Those in the getai industry may have it slightly better.

Mr Peter Loh, whose company Whirltones Entertainment Enterprise is organising about 30 getais this year, said it has not been affected by any price increases.

"We arranged the getais between one and six months ago and prices were fixed then," said Mr Loh, who noted that each getai usually costs around $4,000 to stage.

• Additional reporting by Lim Yan Liang, Lim Yi Han and Audrey Tan