They described scores of undocumented passengers cramming the decks ahead of the disaster on Sunday morning in the Malacca Strait, rejecting the captain’s claims that the ferry went down because of bad weather.

High-school teacher Amir Azli, 56, described scenes of pandemonium on board the Dumai Express as water started to pour through cracks in its hull.

“The skies were clear and the seas were calm when we set sail but the weather turned bad on the way. There was a heavy downpour and huge waves and the ferry was rocking from side to side so vigorously,” he told AFP.

“Children were wailing and women, men, old people all panicked. Many people were crying and vomiting. Some people were so seasick they fainted... even the men. We were all so scared and stressed.”

His account confirms the captain’s claims that the vessel had sailed into an unexpected storm shortly after leaving Batam island bound for Sumatra on Sunday, but the teacher still blamed overcrowding for many of the 29 deaths.

“The ferry was overloaded. My estimate is there were more than 350 people on the boat,” he said as he recovered in Tanjung Balai on Karimun island near Singapore.

The local police chief on Karimun has told reporters as many as 400 people might have been packed on to the 147-tonne craft, well over its capacity of 273 passengers and crew.

The ferry sank less than 30 minutes after it started taking in water, according to the captain Johan Napitupulu, who rejected allegations that it was packed beyond its capacity.

Maritime officials however said there were “indications” of overcrowding and that the accident was under investigation.

“I saw at least 50 people without tickets sitting on the top deck of the ferry. If they had tickets, they should have been in the ferry and not sitting outside,” said Azli, who made it on to one of four lifeboats.

Many of the passengers were on their way to visit families for a Muslim holiday, and were carrying “huge suitcases”, he said.

“It wasn’t just the bad weather. The ferry was overloaded so of course I’m angry that the ferry operator broke the safety rules and people had to die because of that,” Azli said.

“The safety equipment on the ferry also wasn’t up to standard. The life boat I was on leaked and water was getting in as we waited for help.

“All of us had to soak the water with our clothes and wring the water out as we waited.”

He said there was a scuffle between the crew and passengers who were angry that life jackets and boats were not being prepared fast enough.

Another survivor, 25-year-old factory worker Zulfitri, also said she suspected the ferry had too many passengers.

“The ferry was overcrowded with people and things. On the first floor there were people standing because they had no seats,” she said.

She said the crew failed to sound the alarm to abandon ship until it was too late.

“They didn’t tell us there was a problem but only asked us to stay calm. We only realised we were in trouble when we saw the ferry sinking and that’s when we demanded life jackets,” she said.

“My older sister and I managed to put on life jackets and jumped out. We were floating in the water for about four hours before help came. I couldn’t swim and was swallowing so much sea water. I just kept praying.”