BANGKOK (REUTERS) - Fugitive former Thai Prime Minister Thaksin Shinawatra and his sister, former leader Yingluck, were in Singapore on Tuesday (Feb 20), in a rare sighting of them since Yingluck fled Thailand last year, and a day after Thaksin called for unity within his party.

Thaksin and Yingluck were seen at a hotel in Singapore having a conversation with a group of men.

The identity of the men was not immediately clear.

The sighting comes a day after lawmakers from Thaksin's Puea Thai Party said they had flown to Hong Kong at the weekend to meet him. They said Thaksin had called for party unity ahead of an approaching general election.

The Shinawatras have dominated Thai politics for almost two decades despite attempts by their enemies, including those in the military-backed establishment, to weaken the family's political power and undermine their popularity.

Many are watching to see how Thaksin's party performs in a vote which the military government has promised to hold in November but which could be delayed.

Thaksin, who founded Advanced Info Service Pcl, Thailand's largest mobile phone operator, was prime minister from 2001 to 2006, when he was overthrown in a military coup supported by the Bangkok-based establishment.

Thaksin, who is based in Dubai, looms large over Thai politics and remains popular in the north-east and north, which form the stronghold of parties aligned with Thaksin which have won every election since 2001 by appealing to poorer voters.

His sister, Yingluck, was elected prime minister in 2011. She was ousted by a court ruling in 2014, shortly before her government was overthrown in a military coup.

Yingluck fled from Thailand last August, weeks before the Supreme Court found her guilty of negligence in mismanaging a rice subsidy scheme and sentenced her to five years in prison.

Sources in the Puea Thai Party say she is based in Britain.

Thaksin was convicted in absentia in 2006 on conflict of interest charges.

The two have been in Asia since the beginning of the month, said party members, and have visited China, Japan and Hong Kong before travelling to Singapore on Monday.

Mr Prayuth Siripanich, a Puea Thai Party member and its former representative for the province of Maha Sarakham, said 10 lawmakers flew to Hong Kong on Saturday and returned on Monday.

"Thaksin asked lawmakers to be united and not to break that unity," Mr Prayuth told Reuters. "He asked that lawmakers meet their constituents because the election is fast approaching."

Mr Piyapong Klinpan, a spokesman for the junta, or National Council for Peace and Order as it is formally known, told reporters in Bangkok that "relevant agencies", including police, were following Yingluck and Thaksin.

He did not give further details.

Supporters of the Shinawatras say the two are victims of political persecution. Their critics accuse them of widespread corruption, which they deny.

Thaksin and Yingluck are in Singapore at the same time as Thai army chief Chalermchai Sitthisart, who was there to receive an award from Singapore's Defence Ministry.

General Chalermchai told reporters before leaving Bangkok that he was not going to meet the Shinawatras while in Singapore.