This year's presidential poll and parliamentary elections in July come as concerns mount over the failure to use wealth generated by oil and gas sales to support development and create jobs.
"The next five years with new leadership is a critical time because the currently used oil fields are mostly depleted," said Charles Scheiner of La'o Hamutuk, a Dili-based think-tank.
The challenge for any incoming government would be to wean the nation of 1.2 million people off oil and diversify its sources of income into agriculture and manufacturing, he said.
The energy sector accounted for around 60 percent of GDP in 2014 and more than 90 percent of government revenue.
Monday's election, the fourth since independence in 2002, is being contested by eight candidates.
Francisco "Lu Olo" Guterres, backed by the party that led the independence struggle, Fretilin, is a favourite to win the election.
His chances were further enhanced by the endorsement of resistance hero Xanana Gusmao and his CNRT party, said Michael Leach of Australia's Swinburne University.
Police on Friday were keeping an eye on possible unrest as candidates held rallies around Dili.
Supporters of Guterres in convoys of trucks chanted "Viva Lu Olo, Viva Fretilin, Viva CNRT" on their way to a rally about 15km (9 miles) from the capital in Tasitolu.
"If I am later chosen to be president of East Timor, I will prioritise the economic and education sectors, to support the welfare of the people," Guterres said while campaigning.
Another leading candidate is Democratic Party politician Antonio da Conceicao. The education minister has called for "peaceful politics" in a country that has suffered communal violence.
He has the backing his own party as well as the newly formed People's Liberation Party (PLP) of the incumbent president Jose Maria de Vasconcelos.
The president plays a largely ceremonial role, but it is an important post for underpinning unity, particularly with unemployment running at around 60 percent.
Vasconcelos, also know by his former guerrilla nickname "Taur Matan Ruak" (two sharp eyes), is expected to run for the more powerful prime minister's post in the July elections.
The new government will inherit a looming budget crunch as its main source of revenue, the Bayu-Udan field, operated by ConocoPhillips, is set to dry up in the next five years.
That will put pressure on the government to resolve disputes with Australia that are holding back the development of a potential new source of revenue, the Greater Sunrise field.
The field is estimated to hold 5.1 trillion cubic feet of gas and 226 million barrels of condensates, which have been estimated to be worth $40 billion.
The former Portuguese colony was invaded by Indonesia in 1975. A 24-year resistance movement achieved independence in 2002 and many of its key figures still feature prominently in the running of the country.
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First time Timor-Leste citizens can vote for their president from Australia
Presidential Candidate from the Democratic party Antonio da Conceicao speaks to his supporters during a campaign rally in Dili, Timor Leste, 16 March 2017. Source: EPA
