Thai Prime Minister and candidate for the same position Prayuth Chan-ocha, centre, talks with supporters after attending a government-sponsored event in Nakhon Ratchasima. Picture: Sakchai Lalit/AP

Bangkok - With Thailand's first general election since the 2014 coup just two days away, monitoring groups on Friday raised concerns about the transparency of the upcoming polls.

The advance voting held nationwide last Sunday was rife with vote buying and other irregularities, said PollWatch, a local independent group. 

Many voters were reportedly paid between 100 and 2000 baht (3 to 60 dollars) by political parties to attend their rallies, while the ruling military government has raised funding for local communities by 50 per cent one week before the election, the group said.

"[We have] submitted the complaints and some evidence to [the Election Commission], but so far there's no investigation," the group added.

Other irregularities include parties confiscating voters' ID cards, wrong ballots being handed out to voters, lack of transparency in ballot transportation, intimidation of election observers, and lack of clear information about disqualified candidates, another monitoring group We Watch said. 

"We Watch hopes that the Election Commission will fix these mistakes and prevent them from happening again on March 24," the group said. "We want this election to be free and fair."

After five years under repressive military rule, Thais will finally get to decide on their country's leadership.

But political analysts and activists do not consider the upcoming election to be fully free and fair and say it will only lead to semi-democratic rule.