Social affairs official Miska Simanainen said the trial, where people are paid £6,000 ($11,00) a year regardless of whether they have a job or actively look for work, "is proceeding as planned".
However, one of the programme's designers was quoted as saying the "eagerness of the government is evaporating".
The 20 million-euro program, which seeks to reform Finland's social security system, ends in December after which Prime Minister Juha Sipila's center-right government will assess initial results.
Olli Kangas, one of the experiment's designers, had been quoted as saying the government had 'rejected further funding' for the scheme.
Data from the trial, which has captured global attention, is due to be released in 2019, giving experts the opportunity to analyse the merits of the scheme.
Many in Finland, a nation of 5.5 million, have been critical of the idea of handing out cash without first requiring that people work.
Critics feared escalating tax demands on the population. Others said receiving a guaranteed basic income would simply make some unemployed people less inclined to look for a job.
In December, however, the parliament passed a law requiring those receiving benefits to actively seek work - and to provide evidence of their job-hunting every three months.
Meanwhile, there are also reports that the pilot was in placed doubt because Finland is eyeing a new form of welfare programme.
Finland's finance minister, Petteri Orpo, has suggested following up the scheme with a trial of universal credit, a version of which was introduced in Britain in 2013.
This would see a single social security payment that replaces separate benefits like child welfare or income support.
Finnish government agency Kela, which is responsible for the country's social benefits, had hoped the basic income scheme would encourage the recipients to seek employment, boost labour mobility, remove disincentives to work and reduce bureaucracy.
It was part of the measures by the centre-right government of Prime Minister Juha Sipila to tackle Finland's joblessness problem.
In December 2016, just before the trial started, the unemployment in Finland was running at 8.7 per cent. By January this year, 12 months into the two-year pilot, it had barely changed at 8.5 per cent.
Kangas told Finnish broadcaster YLE: "Two years is too short a period to be able to draw extensive conclusions from such a big experiment. We should have had extra time and more money to achieve reliable results."
In an interview with the New York Times, he added: "The government has chosen to try a totally different path. Basic income is unconditional. Now, they are pursuing conditionality."
Heikki Hiilamo, a professor of social policy at the University of Helsinki, told the newspaper: "There is a problem with young people lacking secondary education, and reports of those guys not seeking work. There is a fear that with basic income they would just stay at home and play computer games."
In 2016, the Swiss government held a referendum on whether to pay every citizen around 2,500 Swiss francs ($3,597) per month, but the policy was decisively rejected by Swiss voters.
