Weerasak said the economy appeared to be heading towards a crisis as a result of the government's aggressive stimulus packages over the past five years.

The country faced major economic problems, he said, from rising oil prices, a slowdown in exports due to a stronger baht, rising interest rates, declining consumer purchasing power, and a downturn in the tourism sector.

"If we compare the country to a ship, Thaksin is the captain. He is supposed to be steering the ship but instead he has taken leave.

"Now, the ship is heading for an iceberg and the people cannot wait any longer. If the ship hits the iceberg, Thaksin cannot deny responsibility by saying he can't control the ship," Weerasak said.

"We are not calling for his return, but he must resign or come back to work," he said.

Thaksin's taking leave could not be interpreted as "taking a political break". He had promised on April 4 not to accept the post.

Chat Thai leader Banharn Silapa-archa suggested last week it was time for Thaksin to return to help solve the worsening economic and drug problems.

But former Constitution drafter Kanin Boonsuwan criticised Banharn's suggestion, saying "it was an easy trick" to argue that worsening economic and drug problems warranted his return. "It's not a good reason. When Thaksin was in power, the drug problem was also there," he said.