The first-ever guided nature tours during the Istana open house, which started on Saturday, were sold out.

All 14 tours, each with an average of 12 visitors, were taken up for the Chinese New Year open house on Saturday.

Ms Goh Yinyin, 45, was on the last tour of the day with her parents, who decided to take a day off from the Chinese New Year festivities for a walk around the Istana - open to the public only four times a year. "It was such a surprise to see an oasis in the middle of the city," said Ms Goh, who is self-employed. "And I learned a lot. I never knew Tampines was named after a tree."

About 14 volunteer guides trained by the National Parks Board (NParks) led the tours, which was a new initiative by the President's Office and NParks.

President Tony Tan Keng Yam and his wife Mrs Mary Tan were swarmed by crowds of Singaporeans and tourists as they made their rounds during the open house. Dr Tan told reporters the tours sprung up because many visitors had expressed interest in learning more about the Istana grounds - a "little green lung in the heart of the whole city". The tours will continue to be a feature in future open houses.

He said he hoped the tours would help visitors appreciate the variety of wildlife here, and teach Singaporeans that they all have a role to play in keeping Singapore green. "In a way also, this reflects for us, as Singaporeans, the importance of conservation," he said. "All of us live in an urban society, and we need to have green spaces to keep our wildlife alive, to have plants, to soften the scenery. Otherwise, you are living in a concrete jungle."

He also hoped Singaporeans will visit the parks around the island with their families and "make sure Singapore not only continues to progress and grow in an economic sense, but also in a social and in an environmental sense."

And seeing volunteer guides turn up in full force was a promising sign that Singaporeans cared about each other, and the future. "I think this reflects a good spirit of volunteerism among Singaporeans," he said. "It's a good sign for the future."