The race to choose Sri Lanka's next president has captured the imagination of the island's population.

Varied assignments have taken me to different parts of the country in recent weeks and the most common question I've been asked is "What do you think?"

That level of interest is across the board, from a fisherman in Jaffna, tsunami survivor in Batticaloa, a carpenter in the South and a farmer in the North Central province – it is the same curiosity. Even state employees and a government minister had the same question.

From being an expected walk-over when the president announced his third-term bid, the race is now seen as a close contest.

The reason for the shift? A shock challenger who took everyone by surprise.

Maithripala Sirisena, President Mahinda Rajapaksa's health minister and the General Secretary of the SL Freedom Party doesn't have the charisma or personality of his former boss, but he's clocked more than 40 years’ experience in politics.

His humble demeanor, straight-talking style and quiet confident air seem to be hitting the right chord with thousands of Sri Lankans.

There's disbelief that Sirisena has been able to unite a rainbow coalition of diverse parties - their common goal to defeat Rajapaksa.

President Rajapaksa has dismissed the challenge, but what else can he do but put on a brave face.

Sri Lanka's most popular president could do no wrong a few years ago - to many he still can't.

But the euphoria of the war victory is beginning to fade and people are focusing on more pressing realities.

The rising cost of living, nepotism and cronyism within the government and eroding human rights are beginning to worry people.

It's a fact that is prompting people to think it may be time for change.