Members of the deposed government of former Thai prime minister Yingluck Shinawatra are considering forming a government in exile following last week’s military coup, a senior legal adviser has said, fuelling speculation that Cambodia could play host.

Robert Amsterdam, legal counsel to former prime minister Thaksin Shinawatra (Yingluck’s influential brother), and the United National Front for Democracy Against Dictatorship (UDD), better known as the “red shirts”, said in a statement on Friday that “a number of foreign governments have already expressed their willingness to host such a government in exile under internationally established rules and practice”.

Given its geographical proximity and historic ties to the Shinawatra clan, Cambodia was immediately floated by foreign media outlets as an ideal location. Phnom Penh is little more than an hour by plane from Bangkok, and Prime Minister Hun Sen has welcomed Thaksin warmly in the past.

But senior members of the government and ruling party yesterday rejected the possibility of hosting any such government in exile, citing the constitution, which stipulates “permanent neutrality and nonalignment” and pledges noninterference, either directly or indirectly, in the internal affairs of other states.

“I think whoever feels that Cambodia is an option for a Thai exile government … it is not feasible, firstly because of our constitution, and secondly because we have a comprehensive regional mechanism as well as international [mechanisms],” Council of Ministers spokesman Phay Siphan said.

Information Minister Khieu Kanharith was more blunt.

“We can’t allow such a government on our soil,” he said in a message posted on Facebook.

Since last week’s coup, the government here has been careful to maintain a neutral stance on Thai political issues, but has said it hopes the current military rule will be “transitional”.

General Prayuth Chan-O-Cha, head of the Thai army, has assumed all lawmaking powers in Thailand. Yingluck, fellow politicians and family members were detained by the military, though several media outlets reported last night that the former prime minister had been released.

Earlier this month, before the coup, Hun Sen spearheaded an ASEAN declaration that called for the Thai political situation to be resolved via dialogue and urging “full respect of democratic principles”.

When reached yesterday, Amsterdam, Thaksin’s lawyer, declined to confirm whether Cambodia had been contacted about the government-in-exile proposal.

“We are not discussing anything more than the fact that we are actively considering this. We are not making any statements yet. The situation in Thailand is incredibly fluid. We are preparing but we are not declaring,” he said in a phone interview.

“As a result of that, I don’t want to say anything about who would be the host country.… I’m not going to say anything about where, that doesn’t make any sense at this point.”

Amsterdam added that any government in exile, according to international law, would be “independent of Mr Shinawatra” and dependent on a member of Yingluck’s cabinet who has escaped the country – a person who he declined to name.

“Under international law, we need a representative of the past government.… But Mr Shinawatra continues to be a majorly important political force in Thailand.”

Analysts have long believed that Thaksin was pulling the strings behind his sister’s administration. And if such a move to Cambodia were made, it would not be the first time Thaksin had wedged himself politically between the countries.

After being deposed in Thailand’s last coup in 2006 and fleeing into self-exile to avoid a corruption conviction, Thaksin was made an economic adviser to the Cambodian government and a personal adviser to Hun Sen in 2009, a move that infuriated the conservative Thai government at the time and led to both nations withdrawing their ambassadors.

While Cambodia could be an appealing choice for Thaksin’s new “government”, the former premier might be wary of losing support at home if the military tries “to ratchet up Thai and Cambodian nationalism and connect Thaksin to it”, said Dr Paul Chambers, of the Institute of Southeast Asian Affairs in Chiang Mai, which is affiliated with Chiang Mai University.

“Prayuth might even use a decision by Hun Sen to allow Thaksin a base in Cambodia to take a harder approach on Thai-Cambodian border issues. All of this would be detrimental to Thai-Cambodian relations and the unity of ASEAN,” he said.

“For Cambodia, Hun Sen will have to take a gamble. If Thaksin comes out on the ruling side [in the future], then hosting him makes sense. Otherwise, if Prayuth is the winner here, Hun Sen might want to be careful how he arranges and plays his political poker hand.”

Pavin Chachavalpongpun, a professor of Southeast Asian studies at Kyoto University and a prominent commentator on Thai politics – and one of dozens of academics, activists and journalists summoned by the military in recent days – said he doubted Hun Sen would take such a huge political risk.

“This could resurrect old conflict between Thailand and Cambodia, and I don’t think Hun Sen would want it to happen, not when he [does not have the] upper hand in his own political battle at home,” he said in an email.

Immediately after the coup, Deputy Prime Minister and Minister of Interior Sar Kheng ordered all soldiers and police stationed along the border with Thailand, in addition to provincial governors of border provinces, to continue to cooperate peacefully with their Thai counterparts.

Primary border crossings have remained open in recent days.

Foreign Ministry spokesman Koy Koung said that Thai Embassy staff remained in place yesterday and he had not received notification of any changes since the coup.

He declined to comment on the prospects of Thaksin being allowed to set up a government in exile in Cambodia.

Despite citing the constitution to explain why a government in exile couldn’t be set up in Cambodia, senior ruling party lawmaker Cheam Yeap appeared to say that if Hun Sen wanted to go through with it, he could.

“The constitution does not allow another country to use Cambodia’s sovereignty to set up an armed force or government.… However, related to Thaksin’s announcement … I don’t know, it depends on the sentiment between Thaksin and Samdech Techo Hun Sen or leaders of the ruling Cambodian People’s Party.”